A multiuser communication method for Code Division Multiple Access, CDMA, applied to a transmitter and comprising: acquiring N modulated symbols which are obtained by modulating a code block coded by a channel coder, where N is a positive integer more than or equal to 2; spreading the N modulated symbols according to N spread sequences with a specified length, wherein there are at least two different spread sequences in the N spread sequences with the specified length, wherein the N spread sequences comprise: complex sequences; and transmitting the spread modulated symbols; wherein the complex sequences are determined in the following manner: generating real parts and imaginary parts of all complex elements in the complex sequences by virtue of a Pseudo-Noise, PN, sequence generator capable of generating M-ary real numbers, or selecting real parts and imaginary parts of all complex elements in the complex sequences from an M-ary real number set according to a specified PN criterion, where M is an integer more than or equal to 2, preferably, a value of M comprises at least one of: 2, 3 or 4; and determining the complex sequences according to the selected real parts and imaginary parts of all the complex elements; wherein the complex sequences are determined in the following manner: generating a first real sequence with a length R and a second real sequence with a length R according to the M-ary real number set, wherein both the first real sequence and the second real sequence adopt values in the M-ary real number set, where R=N×L, and L is a value of the specified length; determining an ith element of the first real sequence as a real part of a complex sequence, determining an ith element of the second real sequence as an imaginary part of the complex sequence, and determining a complex number comprising the real part and the imaginary part as an ith complex element of the complex sequence, where i=1,2,3......,R; and sequentially arranging R obtained elements to form the complex sequence with the length R, and equally dividing the complex sequence with the length R into N complex sequences with the specified length. acquiring N modulated symbols which are obtained by modulating a code block coded by a channel coder, where N is a positive integer more than or equal to 2; spreading the N modulated symbols according to N spread sequences with a specified length, wherein there are at least two different spread sequences in the N spread sequences with the specified length, wherein the N spread sequences comprise: complex sequences; and transmitting the spread modulated symbols; wherein the complex sequences are determined in the following manner: generating real parts and imaginary parts of all complex elements in the complex sequences by virtue of a Pseudo-Noise, PN, sequence generator capable of generating M-ary real numbers, or selecting real parts and imaginary parts of all complex elements in the complex sequences from an M-ary real number set according to a specified PN criterion, where M is an integer more than or equal to 2, preferably, a value of M comprises at least one of: 2, 3 or 4; and determining the complex sequences according to the selected real parts and imaginary parts of all the complex elements; wherein the complex sequences are determined in the following manner: generating a first real sequence with a length R and a second real sequence with a length R according to the M-ary real number set, wherein both the first real sequence and the second real sequence adopt values in the M-ary real number set, where R=N×L, and L is a value of the specified length; determining an ith element of the first real sequence as a real part of a complex sequence, determining an ith element of the second real sequence as an imaginary part of the complex sequence, and determining a complex number comprising the real part and the imaginary part as an ith complex element of the complex sequence, where i=1,2,3......,R; and sequentially arranging R obtained elements to form the complex sequence with the length R, and equally dividing the complex sequence with the length R into N complex sequences with the specified length. generating real parts and imaginary parts of all complex elements in the complex sequences by virtue of a Pseudo-Noise, PN, sequence generator capable of generating M-ary real numbers, or selecting real parts and imaginary parts of all complex elements in the complex sequences from an M-ary real number set according to a specified PN criterion, where M is an integer more than or equal to 2, preferably, a value of M comprises at least one of: 2, 3 or 4; and determining the complex sequences according to the selected real parts and imaginary parts of all the complex elements; wherein the complex sequences are determined in the following manner: generating a first real sequence with a length R and a second real sequence with a length R according to the M-ary real number set, wherein both the first real sequence and the second real sequence adopt values in the M-ary real number set, where R=N×L, and L is a value of the specified length; determining an ith element of the first real sequence as a real part of a complex sequence, determining an ith element of the second real sequence as an imaginary part of the complex sequence, and determining a complex number comprising the real part and the imaginary part as an ith complex element of the complex sequence, where i=1,2,3......,R; and sequentially arranging R obtained elements to form the complex sequence with the length R, and equally dividing the complex sequence with the length R into N complex sequences with the specified length.