An SDN (Software Defined Networking) system with auto-deployment switches and a method for auto-deploying the switches in said SDN system are proposed. The method includes: actively sending a configuration message out by a controller, with said configuration message having an IP (Internet Protocol) address of the controller and a plurality of parameters; receiving the configuration message by a switch; and building a connection between the switch and the controller according to the IP address of the controller and the plurality of parameters.