The invention provides an active and passive radar composite seeker processor system based on a VPX architecture. The signal processor comprises a processor backboard, an interface timing sequence unit, an active acquisition and emission unit, a passive acquisition and processing unit, a radar signal processing unit and a radar image processing unit, and each unit performs data interaction with other units in the signal processor through SRIO, RS485, GPIO and other interfaces. Different cells are combined, and three working modes, namely active radar SAR imaging, active radar monopulse and passive radar work modes, can be independently adopted; and the functions of large forward inclination SAR imaging, SAR image matching and positioning in an active radar SAR imaging mode, target detection, distance measurement, angle measurement and tracking in an active radar monopulse model, target searching and direction finding in a passive radar mode and the like are realized. The system meets the integrated requirements of the three work modes, and the radar signal processing unit can be used for receiving a control instruction to complete switching among the modes.