The invention discloses a mainboard of a microcomputer protective device, which takes a 32-bit DSP as a core and mainly comprises a CPU module and a 14-bit sampling module connected with the CPU module. A double-port SRAM, a CPLD logic device, a CAN bus module and a communication module are also arranged in the mainboard; the CPU module comprises a CPU management module and a DSP central processing module; the CPU management module, the double-port SRAM and the DSP central processing module are sequentially connected through bidirectional buses; at the same time, the CPU management module is also connected with the CPLD logic device and the communication module, and the sampling module and the CAN bus module are also connected with the DSP central processing module. A modular circuit with multiple functions is also arranged in the mainboard, such as a warning device, a display module, a clock module, etc. The mainboard has the advantages of strong function, high processing speed, high informatization level, convenient data sharing, good stability, etc., and is mainly used in the microcomputer protective device.