Abstract: A encoder based on the kernel idea of EZW,the zerotree coding and the SAQ,is redesigned.According to this encoder,the satellite images (after WT) are encoded.The compress effect of zerotree coded satellite images is analyzed.By adopting six-symbol zerocoding symbol set,the “dominant”pass and the “subordinate”pass in EZW algorithm are combined.In the procedure of encoding the zerotree-symbol bit-stream by a lossless method,the compress effect of several other algorithms but the adaptive arithmetic coding method is compared and a more suitable lossless coding algorithm is proposed according to the experimental results.