Nowadays, the energy issue has become a hot topic in many fields, therefore, the mobile electric energy efficiency detection system with considerable advantages in energy service is proposed. It can efficiently detect the state data and energy efficiency data of energy-using equipment, and analyze the data through an energy analysis model then a corresponding energy assessment report is generated. A mobile electric energy efficiency detection system based on Linux QT is introduced in this paper, which provides a feasible idea for embedded energy efficiency monitoring. QT GUI library is used to develop the system interface, which can display and query the real-time data, events conveniently. After a series of tests, the system can detect the energy efficiency accurately.