Sensor network access control method and system with low expenditure

The invention relates to a sensor network access control method and a system with low expenditure. The system comprises a user, a destination node (DN) and an access controller (AC). Before a protocol operates, secrete keys are shared between the user and the AC as well as between the DN and the AC; and in the process of authenticating the user by the DN in a sensor network, the users forwards the authentication information between the DN and the AC, and then the DN performs entitlement management on the user without other nodes in the sensor network to participate in the authentication process, thus preventing communication expenditure from occurring due to forwarding authentication information between the user and the DN by nodes in the network, effectively saving node resources, realizing lightweight and efficient access control, prolonging network service life and lowering utilization cost especially for a sensor network accessed by a large number of users frequently.