The invention discloses an image data processing method for accelerating data transmission wherein, the X digit two-valued digital signal is transformed into the two-valued compressed data having thefloating-point number compressed format to export in the format of a string of binary number representing an (m, n) array the last n digit of which are composed of the X bit binary digital signal. The image data compression method in the invention can reduce data-transmission volume, shorten transfer time and at the same time reduce the data storage space for storing the image data.