In multi-controller Software Defined Network (SDN), since the existed switch migration strategies always have low efficiency and need to migrate many times which only consider single migration factor, a mechanism of switches migration based on progressive auction named PASMM (Progressive Auction based Switches Migration Mechanism) was proposed. To improve network benefit, the switch migration problem was optimized by auctioning controllers' remaining resources in the mechanism. By increasing the trading price of the over-demanded controllers' resources, PASMM completed the auction and redeployed the controllers and switches. The simulation results show that, compared with some typical switch migration policies, PASMM achieves good load balancing of controllers, reduces the response time of the PACKET_IN messages by an average of 13.5%, and spends the least migration time with the increasing of switches flow requests.