Abstract: This paper analyzes the significance, feasibility and key issues of the GPS, GLONASS, BD, Galileo multi-system compatibility and proposes a multi-system compatible method in GNSS receiver based on SoC. A number of measures, such as IF sampling technique, time-frequency two-dimensional weak-signal fast acquisition technology, memory-code based correlation channel and SoC based signal processing method, were adopted to deal with the compatibility issues. With the compatible antenna and RF module, the GNSS receiver could solve and realize the sampling, capturing, tracking and other aspects of multiple system compatibility. The implementation details of proposed GNSS receiver were given with its architecture and process flow. A verification system has been built to realize compatible signals' tracking of multiple navigation systems.