At present, the primary and secondary deep fusion sensor applies in the field of distribution network automation more and more popularly. In order to realize the traceability of the weak output AC sensor and establish the corresponding error calibration system, the active V/I conversion capacitor voltage divider is developed as a standard device in this paper. A precision voltage matching unit is designed to solve the problem of voltage un-matching between the standard device and the sensor under test. Through the design of the multi-stage shielding structure, secondary series boost coil and dynamic following feedback circuit, the inverse and proportional boost functions of precision voltage matching unit are realized. Finally, the error calibration of weak output voltage sensor based on different principles is realized with two-channel precision error measurement system.