The present invention provides a display screen control circuit of an electric power instrument. The circuit comprises an MCU, an LCD, a pull-up resistor R2, a triode and a resistor. The model of the MCU is PIC18F45K80; the pull-up resistor R2 is an adjustable resistor; the base electrode of the triode is divided into two ways after passing through the resistor, one way is connected with the MCU, and the other way is connected with a VCC after passing through the R2; and the emission electrode of the triode is grounding, and a collector is connected with the VCC through the LCD. The pull-up resistor R2 is added, when the MCU-COL base pin of the MCU is arranged at a high position, the triode is conducted, and the LCD is bright; when a backlight lamp is closed, the MCU-COL base pin of the MCU is arranged at the input state, the MCU-COL base pin is a high-resistance state, and small current is flowed from the triode to allow the LCD to be located in the fine-light state; the bright and dark degrees of the backlight lamp is adjusted by adjusting the size of the pull-up resistor R2. The circuit is simple in design, and the display is long in usage time.