In order to solve the problem of complex driving and high requirement of processor in TFT LCD, a display system is designed to drive the TFT LCD with MUC interface through serial port control. The hardware of the system is composed of STM32F4 processor and TFT LCD. Stm32f4 is used to drive TFT LCD and provide control channel to the external processor using TFT LCD display system through its serial port. The software uses μC/OS-Ⅲ operating system to write the bottom driver and driver control interface program, and uses DMA to read the serial port data. The hardware interface of the system is simple, only two I/O lines are needed to control the TFT LCD. The system can support four external processors to control the TFT LCD through the serial port. The serial port transmission rate is 2.4 kB/s~2 MB/s. The experimental results show that the system is stable and reliable, the display effect is clear and smooth, the drive and use of TFT LCD are simplified, and the adaptability and use range of TFT LCD are expanded.