In order to meet multi-channel, high data rate, intensive computing capacity of modern radar signal processing, a standard, scalable, high-performance general-purpose radar signal processing system platform is proposed. The main processor of this system platform is the DSP and FPGA. In the analysis of different kinds of radar signal processing algorithm, and taking into account the respective advantages and disadvantages of DSP and FPGA, In this paper, a software architecture method for radar signal processing is given to decide how to distribute different algorithm into DSP and FPGA. At last, for a certain type of circular array radar, an implementation of radar signal processing by using the general-purpose radar signal processing system platform is proposed.