An image coding method, comprising: performing matching coding on pixels of an input video image to obtain one or more matching relationship parameters, wherein the matching relationship parameters are parameters used in a process of constructing predicted values or reconstructed values of the pixels in the input video image; the matching relationship parameters comprise at least one of: displacement vector, a component of a displacement vector, a height of a matching rectangle, a width of a matching rectangle, a height of a matching right trapezoid, a width of the upper side of a matching right trapezoid, a width of the lower side of a matching right trapezoid, numbers of a plurality of preset matching square blocks with definite size, lengths of I horizontal lines when a matching region is constituted by the I horizontal lines; mapping the matching relationship parameter to obtain a mapped value of the matching relationship parameter; and performing entropy coding on the mapped value of the matching relationship parameter; wherein the value range of a certain matching relationship parameter is an integer interval from 1 to 12288; and mapping the matching relationship parameters comprises: mapping the matching relationship parameter to obtain a mapped value of the matching relationship parameter according to below mapping formulas: 4k is mapped to k, in which k=1, 2, 3, 4,...... 3072; 4k+1 is mapped to 3072+3k+1, in which k=0, 1, 2, 3,...... 3071; 4k+2 is mapped to 3072+3k+2, in which k=0, 1, 2, 3,...... 3071; and 4k+3 is mapped to 3072+3k+3, in which k=0, 1, 2, 3,...... 3071; corresponding to mapping a value of the matching relationship parameter with a higher appearance frequency in the value range into a smaller value and mapping a value of the matching relationship parameter with a lower appearance frequency in the value range into a larger value. performing matching coding on pixels of an input video image to obtain one or more matching relationship parameters, wherein the matching relationship parameters are parameters used in a process of constructing predicted values or reconstructed values of the pixels in the input video image; the matching relationship parameters comprise at least one of: displacement vector, a component of a displacement vector, a height of a matching rectangle, a width of a matching rectangle, a height of a matching right trapezoid, a width of the upper side of a matching right trapezoid, a width of the lower side of a matching right trapezoid, numbers of a plurality of preset matching square blocks with definite size, lengths of I horizontal lines when a matching region is constituted by the I horizontal lines; mapping the matching relationship parameter to obtain a mapped value of the matching relationship parameter; and performing entropy coding on the mapped value of the matching relationship parameter; wherein the value range of a certain matching relationship parameter is an integer interval from 1 to 12288; and mapping the matching relationship parameters comprises: mapping the matching relationship parameter to obtain a mapped value of the matching relationship parameter according to below mapping formulas: 4k is mapped to k, in which k=1, 2, 3, 4,...... 3072; 4k+1 is mapped to 3072+3k+1, in which k=0, 1, 2, 3,...... 3071; 4k+2 is mapped to 3072+3k+2, in which k=0, 1, 2, 3,...... 3071; and 4k+3 is mapped to 3072+3k+3, in which k=0, 1, 2, 3,...... 3071; corresponding to mapping a value of the matching relationship parameter with a higher appearance frequency in the value range into a smaller value and mapping a value of the matching relationship parameter with a lower appearance frequency in the value range into a larger value. mapping the matching relationship parameter to obtain a mapped value of the matching relationship parameter according to below mapping formulas: 4k is mapped to k, in which k=1, 2, 3, 4,...... 3072; 4k+1 is mapped to 3072+3k+1, in which k=0, 1, 2, 3,...... 3071; 4k+2 is mapped to 3072+3k+2, in which k=0, 1, 2, 3,...... 3071; and 4k+3 is mapped to 3072+3k+3, in which k=0, 1, 2, 3,...... 3071; 4k is mapped to k, in which k=1, 2, 3, 4,...... 3072; 4k+1 is mapped to 3072+3k+1, in which k=0, 1, 2, 3,...... 3071; 4k+2 is mapped to 3072+3k+2, in which k=0, 1, 2, 3,...... 3071; and 4k+3 is mapped to 3072+3k+3, in which k=0, 1, 2, 3,...... 3071; corresponding to mapping a value of the matching relationship parameter with a higher appearance frequency in the value range into a smaller value and mapping a value of the matching relationship parameter with a lower appearance frequency in the value range into a larger value.