AC charging spot on-site tester is mainly applied to field verification of AC charging facilities, and it has been widely used in metrology and electric power institutes. With the emphasis on the reliability of charging process, interoperability test has also become the focus of field test. In view of increasing demand of verification and interoperability test, a high-integrated new type of on-site tester is developed. The electrical energy calibration technology is discussed, and the calibration system principle, resolving methods for technical difficulties are introduced in detail. Compared with the traditional interface circuit simulator, this equipment can reduce equipment transportation and wiring work. Through practical experiments, it can be concluded that this equipment can effectively complete the field verification and interoperability test of AC charging spot.