The invention relates to a method for signal processing used in terminal device of code division multiple access mobile communication system, the method is a combining of time diversity and joint detection in order to increase diversity gain of receiver. The method includes steps: make a multitude sampling for received signal in time domain; estimate impulse response of air channel; obtain matrices; constitute a system matrix; perform joint detection algorithm, attain estimation of original transmitting data. When the method is used at mobile terminal, the problem of imbalance between uplink and downlink performance so that frequency reuse can be achieved, and relatively simple joint detection can be used. The method could also be applied in base station.