A 2D barcode-based bi-directional wireless transmission system includes a first apparatus and a second apparatus each including a display screen, a processing system and a camera. The first apparatus encodes a data to be sent into multiple 2D barcode images and sequentially displays these multiple 2D barcode images on the display screen thereof so that the second apparatus sequentially captures the multiple 2D barcode images from the first apparatus, and then decodes the captured multiple 2D barcode images into a received data, and then encodes a feedback information into a 2D barcode image and displays on the display screen thereof for allowing the first apparatus to capture and then to decode the captured 2D barcode image of the feedback information so as to obtain the feedback information.