This design is a tester designed to accurately measure AC voltage signals. This design uses stm32 as the core processor, uses a voltage transformer to step down the original signal, and combines the MCP6292 operational amplifier to cleverly design a signal conditioning circuit so that the input voltage can meet the voltage measurement range of STM32. The analog signal is sampled at equal time intervals by the successive integration algorithm to obtain its effective value. Then through the built-in AD conversion module on the stm32 processor chip, the signal is converted to analog to digital. Finally, the converted value can be displayed on the screen through the LCD, and the measured data can be displayed on the upper computer terminal at the same time. Through the observation of the measured data, it can be found that the design can accurately measure the AC voltage. Compared with the traditional measurement method, the design can improve the measurement accuracy and improve the stability and power consumption.