The utility model discloses a portable intelligent electricity stealing detection instrument, comprising a microprocessor and a display connected with each other. On input end of the microprocessor is connected with a signal gatherer via an A/D converter, and the other input end of the same is connected with a pulse signal receiver via a counter; and the microprocessor is also connected with a keyboard and a battery module respectively. The signal gatherer comprises a voltage gatherer and a current gatherer. According to the utility model, the design of an embedded microprocessor is employed, and the circuit is simple and reliable; electricity quantity information and electricity quantity data of user ammeters are automatically gathered via program design, and the electricity quantity information and the electricity quantity data of user ammeters are automatically compared to provide a reliable judging data of electricity stealing states for staff in an electric power company; and metering units are used to carry out final judgment so as to achieve the goal of preventing electricity stealing.