At present, Monitor manufacturersECG monitors from monitor manufacturers are indispensable instruments for first aid and intensive care in hospitals at all levels. The LCD screen of monitors is a vulnerable part, and it is expensive, which is generally more than several units. Moreover, the size, data interface and power supply voltage of LCD screens of monitors of different models are different, which brings many difficulties to maintenance and replacement. This paper introduces an inexpensive way to repair the LCD screen. 1. Confirm that the power supply is normal and the power indicator is on. 2. After the power is cut off, open the back cover of the instrument, find the switching power supply board and high voltage output circuit board, and measure whether the DC 5V power supply and high voltage output are normal. The specific method is as follows: unplug the plug on the high-voltage power supply board, and measure the DC 5V after power-on: plug in the plug, contact any pin on the output end of the board with a multimeter probe, and find a slight discharge cremation, which proves that the high-voltage output is normal, and it can be judged that the high-voltage backlight in the LCD screen is damaged. 3. Irradiate the back of the LCD screen with a strong light source, turn on the power supply of the instrument, and observe the original data information in front of the screen, indicating that the LCD screen can be modified. 4. A self-made circuit board (10crn×O．5em) is composed of 9 self-luminous high-brightness LEDs and a 1N4007. 5. Carefully open the side of LCD without data cable a little, subject to the light guide glass. Then fix the self-made circuit board on this side with hot melt adhesive, unplug the power supply plug of the high-voltage power board and connect it to the self-made circuit board.