The invention discloses a pulse Doppler radar system based on multiple detection signals and a signal processing method. The pulse Doppler radar system comprises a plurality of transmitters, wherein each transmitter respectively transmits orthogonal pulse detection signals synchronously at different pulse repetition frequencies (PRF), and the PRF of different detection signals meet stagger relationship, the receiving system of airborne radar is composed of a receiver or a plurality of receivers. The signal processing method processes the echo corresponding to different transmission signals via target detection, to obtain respective target detection results. The interference accumulation time of the pulse Doppler radar can be significantly prolonged under single PRF, thereby improving target detection performance. The invention utilizes the stagger relationship among different PRF, to process ambiguity resolution treatment on the detection result having distance and Doppler ambiguity under different PRF, to obtain correct target distance and Doppler information.