Doppler speed radar is a high precision velocity measuring instrument based on Doppler Effect, which has widely applications in measuring moving target’s velocity. In this paper, a novel design of Doppler signal processing system was presented to perform projectile’s speed measurement tasks. The system architecture is based on an Altera Cyclone II chip and designed as a System-on-a-Programmable-Chip (SOPC) with the help of an embedded Nios II software processor. And the SOPC system integrates CPU, memory, I/O interface and some other reconfigured modules required in system. According to the proposed scheme, the peripheral circuits were designed in this system, such as signal condition, A/D conversion and auto gain control (AGC) circuit. We also proposed to use spectral analysis method based on windowed FFT to deal with the measured target’s Doppler signal. Further, the signal source of simulating targets was used to testify the system feasibility. In addition, future work can include the further study on frequency estimation algorithms or comparisons of the proposed architecture with traditional design.