This paper presents a hardware and software design scheme of a low voltage relay protection device integrated with measurement and control based on power dedicated multi-core heterogeneous chip. Combining with the basic structure of power dedicated multi-core heterogeneous chip，this paper describes the overall design of highly integrated low-voltage protection device integrated with measurement and control； designs the external interface of hardware for low-voltage all-in-one and standby self-switching devices； expounds the design of software system architecture and the allocation of device functions among multi-cores，focusing on power dedicated algorithm，real-time data flow based on pre-data processing and calculation of electrical parameters，and the abstraction of peripheral device access. The optimized multi-core communication mechanism is analyzed. Function and performance of the low-voltage protection device integrated with measurement and control based on the chip has been verified at the low-voltage side of a 110 kV substation，and the feasibility of the scheme is verified by the test results.