Abstract: Based on the wavelet transform of image，the conventional ROI progressive transmission algorithm is improved using visual masking effect.On the premise of the high quality of ROI image，the important coefficients for human vision will be transmitted firstly.And a flexible background image transmission mechanism is proposed.An expansion factor S is introduced in order to indicate the importance of BG image relative to ROI.Moreover，depending on different network bandwidth，the factor can be used to control the BG image transmission mode so as to assure that the whole image have good objective visual effect.In the simulation experiment，the objective and subjective comparative analysis between conventional algorithm and improved algorithm will be made.Eventually，the experimental results proved the validity of the proposed algorithm.