The invention provides a SDN authentication method based on trust management. The method includes the following steps: combining cryptology with hardware devices, establishing a SDN authentication model based on trust management; acquiring access authority through single point sign in; with the proviso of evaluating access safety level and allocating limit session time for a user, establishing a TMUAM mechanism; and authenticating the user. The method can control abnormal behaviors and threats by evaluating the user and terminal behaviors, and addresses the safety hazards of a SDN controller.