For the problem that it is difficult to prevent the low voltage large user and low business users from stealing electricity, the paper puts forward the overall design scheme of smart electric control device and the methods of low voltage large users remote monitoring and data acquisition analysis, researches the highly integrated technology of MCCB, low-voltage current transformer, three-phase electric energy meter, designs software architecture of the low voltage large user intelligent power monitoring device, researches of hardware and software initialization program, device communication module program and monitoring control program. A set of low voltage large user intelligent power monitoring device including power monitoring, remote control and other functions is successfully developed, it realizes the remote monitoring of electrical data and the abnormal electrical control of low-voltage large users, solves the problem of low voltage large users fine line loss analysis and remote control. The application shows that the device is advanced in technology, convenient to use and practical, it is conducive to carrying out meticulous line loss management and cracking down on electricity stealing in power supply enterprises. It has strong practical value and broad application prospects.