In order to solve the problem of site selection of grain emergency supply location,we established a corresponding optimization model to achieve the targets of the shortest transport time and the earliest emergency start time.We solved the model by use of a particle swarm-based k-medoids cluster algorithm,and we also put forward a self-adaptive chaos particle swarm optimization algorithm to avoid the solution from sinking to local optimum prematurely.The algorithm judged the current state of the particle swa...