The premise of research on the development of the design of voltage monitoring instrument, the application of the system structure, functional requirements, performance index and core encryption terms of hardware, according to the characteristics of embedded system, mainly from the system memory,communication module, encryption module, communication interface module, sampling module and power supply monitoring and clock design aspects of the hardware design of voltage monitoring the aspect of software, to achieve accurate measurement of voltage, using the standard table calibration voltage compensation design of voltage monitor; for subsequent mass production, software design using message field work mode using the data frame format design of batch configuration of terminal information; the encrypted transmission of data by computing the unique encryption algorithm after transmission, the decryption in the master station.