In order to solve the problems of extending the display effect of the LCD image through the LED light bar and synchronizing the display of screen color of LED light bar in real time,an ambient light control technology scheme based on SPI bus is proposed.The software algorithm is used to automatically partition the LCD image,analyze the image data of the sub-block of the partition image,and a deep fusion image algorithm is used to produce RGB data that controls ambient light.The LED driver chip TLC5971 is cascading connection for controlling the LED bar display of the corresponding partition.The main controller transmits the RGB data of the partitioned image to TLC5971 through SPI bus to control the LED light bar to display the screen color in real time,so as to achieve the LCD screen extension.