The invention discloses a voltage transformer with high heat dissipation performance. The voltage transformer comprises a voltage transformer body, a heat dissipation port is arranged at a front end of an upper portion of the voltage transformer body, a supporting shell is fixedly arranged at the bottom of the voltage transformer body, and a pedestal is fixedly arranged at a lower end of the supporting shell. A semiconductor refrigeration sheet is fixedly installed in the supporting shell. A fan is installed on the supporting shell. An air outlet pipe is installed at air outlet of a right sideof the fan. The right side of the semiconductor refrigeration sheet is connected with a connecting pipe, the upper end of the connecting pipe is fixed and connected with the voltage transformer body,a refrigerating surface of a rear end of the semiconductor refrigeration sheet is located between the fan and the connecting pipe, and the connecting pipe is located on the right side of the refrigerating surface of the rear end of the semiconductor refrigeration sheet. A problem that an existing voltage transformer has a poor heat dissipation effect is solved.