The two-order particle swarm optimization algorithm was presented by Hu Jianxiu and Zeng Jianchao in 2007. The standard particle swarm optimization algorithm and the two-order particle swarm optimization algorithm are studied in the paper. This paper uses the modified two-order particle swarm optimization algorithm to carry out muIti threshold image segmentation. The experimental results show that the multi-threshold image segmentation method based on the modified two-order particle swarm optimization algorithm could segment the image effectively.