This study presents a dynamic simulation of a purse seine net behavior Mathematical model suitable for purse seining, which is based on data from a series of previous simulations, various field experiments, is modelized as a set of mass-spring system. In this model, a number of meshes are approximated as one mass point, each of which connected to its neighbors by massless springs, the equations of motion are derived from considering internal force from the springs and external forces such as resistance and gravitation. This simulation shows the quantitative state on every mass point of the net and purse line during the shooting and pursing phases. So it is possible that performance of a purse seine net be analyzed using various and evolving parameters such as the shooting speed, the hauling speed, the size or type of the sinker, float and twine, also the hanging ratio etc.