The building of harmonic voltage source is the one of key issues in harmonic characteristic measurement of voltage transformer. It is required to output large capacity and controllable harmonic components, but the existing harmonic sources cannot satisfy these requirements. To solve the problem, this paper refers the scheme of IGBT single-phase inverter as the core to build the controllable harmonic voltage source. The working principle of the controllable harmonic voltage source is introduced, the system parameters are designed and simulated and the characteristics of the controller are analyzed. The simulation results show the feasibility of the proposed scheme. On this basis, the VT harmonic characteristic measurement platform is built. The output results further verify the effectiveness of the scheme, which lay the foundation for harmonic characteristic measurement and test study of the voltage transformer.