A method for transmitting a reference signal in a communications system, wherein the communications system comprises a terminal and a base station, and the method comprises: determining, by the terminal, a parameter based on frequency domain location information of a frequency domain resource unit, wherein the parameter is used to determine a sequence of the reference signal, and the reference signal is carried on the frequency domain resource unit; and sending, by the terminal, the reference signal to the base station, or receiving, by the terminal, the reference signal sent by the base station; wherein the terminal determines the parameter based on the frequency domain location information of the frequency domain resource unit and identification information of a cell in which the terminal is located; wherein the terminal belongs to a first cell, frequency domain resource units of the first cell comprise a first frequency domain resource unit and a second frequency domain resource unit, the parameter comprises a first parameter and a second parameter, the first parameter is used to determine a sequence of a reference signal carried on the first frequency domain resource unit, the second parameter is used to determine a sequence of a reference signal carried on the second frequency domain resource unit, and the first parameter is different from the second parameter; wherein the communications system further comprises a second cell, and the parameter for the frequency domain resource unit varies between the first cell and the second cell, wherein, for the first cell, parameters of a sequence of the reference signal constitute a first parameter set and for the second cell, parameters of a sequence of the reference signal constitute a second parameter set, wherein the first parameter set is the same as or partially overlaps with the second parameter set; wherein full bandwidth or a sub-band of the communications system includes n frequency domain resource units with contiguous frequency domain locations, and n parameters are successively allocated to the n frequency domain resource units with contiguous frequency domain locations in an order of a 1+x, a 2+x,..., and a (n+x)%n, where X is determined based on identification information of a cell, and % is a remainder operation symbol; or n parameters are successively allocated to the n frequency domain resource units with contiguous frequency domain locations in an order of a 1+x, a 2+x,..., and a (n+x), where X is determined based on identification information of a cell. determining, by the terminal, a parameter based on frequency domain location information of a frequency domain resource unit, wherein the parameter is used to determine a sequence of the reference signal, and the reference signal is carried on the frequency domain resource unit; and sending, by the terminal, the reference signal to the base station, or receiving, by the terminal, the reference signal sent by the base station; wherein the terminal determines the parameter based on the frequency domain location information of the frequency domain resource unit and identification information of a cell in which the terminal is located; wherein the terminal belongs to a first cell, frequency domain resource units of the first cell comprise a first frequency domain resource unit and a second frequency domain resource unit, the parameter comprises a first parameter and a second parameter, the first parameter is used to determine a sequence of a reference signal carried on the first frequency domain resource unit, the second parameter is used to determine a sequence of a reference signal carried on the second frequency domain resource unit, and the first parameter is different from the second parameter; wherein the communications system further comprises a second cell, and the parameter for the frequency domain resource unit varies between the first cell and the second cell, wherein, for the first cell, parameters of a sequence of the reference signal constitute a first parameter set and for the second cell, parameters of a sequence of the reference signal constitute a second parameter set, wherein the first parameter set is the same as or partially overlaps with the second parameter set; wherein full bandwidth or a sub-band of the communications system includes n frequency domain resource units with contiguous frequency domain locations, and n parameters are successively allocated to the n frequency domain resource units with contiguous frequency domain locations in an order of a 1+x, a 2+x,..., and a (n+x)%n, where X is determined based on identification information of a cell, and % is a remainder operation symbol; or n parameters are successively allocated to the n frequency domain resource units with contiguous frequency domain locations in an order of a 1+x, a 2+x,..., and a (n+x), where X is determined based on identification information of a cell.