The apparatus comprises a correction unit composed of a video camera module for capturing the color information of the screen, an image data buffer module, and a main control module used for receivingand executing the computer command. Said video camera module and image data buffer module are respectively connected to the multi-screen display wall and computer via the main control module. The method comprises: appointing the image displayed by each display unit on the multi-screen display wall; said video camera module shoots at least one picture and saves it in the image data buffer module;the computer extracts the color information from each display unit; according to the color of each display unit, the computer corrects the difference between said display units.