Abstract：The algorithm of Set Partitioning in Hierarchical Trees (SPIHT) is well known for its simplicity and efficiency. However, the use of three lists(LSP, LIP and LIS list) requires a high, variable and data dependant memory. Besides this, a repeated scanning also reduces the algorithm's efficiency to make it difficult for the SPIHT algorithm to be implemented in a hardware platform, especially for low memory and real time applications. In order to solve this problem, a modified listless SPIHT based algorithm is proposed in this paper. Firstly, the state mark matrixes are used to replace three lists (LSP, LIP and LSP list) for the significant information, and the modified SPIHT algorithm saves memory and avoids the dynamic memory management. The use of the maximum value array and the number of the maximum output bits also reduces the degree of scanning in the sorting pass and enhances the algorithm's efficiency. Secondly, in the modified SPIHT algorithm a new test is added for the type A set to optimize the output bit stream, which improves the algorithm's performance.