A frame data shrinking method is disclosed. The method is to divide frame data into data of target pixel and neighbor pixels, and select one data combination set from a plurality of data combination sets provided from the data neighbor pixels as encoded data of the target pixel; and the data combination set are to be compressed and recovered as decoded data of the target pixel of the current frame for being used to be compared with the decoded data of a target pixel of a previous frame; and then the data of the neighbor pixels are compressed and stored along with the selection information about the target pixel in a memory. Because the usage of memory is relatively lower, the cost of driving chips can be effectively reduced.