Matlab code for the paper "HUANG Ke-kun. Improved Set Partitioning in Hierarchical Trees Algorithm Based on Adaptive Coding Order[J], Journal of Computer Application, 2012, 32(3):732-735." In order to obtain better compression on image edge, an improved Set Partitioning In Hierarchical Trees (SPIHT) algorithm based on prior scanning the coefficients around which there were more significant coefficients was proposed. The coefficients or sets were sorted according to the number of surrounding significant coefficients before being coded, and the previous significant coefficients were refined as soon as the sets around which there existed any significant coefficients had been scanned. The scanning order was confirmed adaptively and did not need any extra storage. It can code more significant coefficients at a specified compression ratio. The experimental results show that the method can improve PSNR and the subjective visual experience compared with SPIHT.