Disclosed a system and method for mutual authentication between a node and a sink in a sensor network. At least one sink periodically creates a neighboring sink list including information on at least one adjacent sink, and the sink requests node authentication to a base station when receiving an authentication request from the node and transmits its own neighboring sink list to the node when the node authentication has been completed. When the node moves and requests authentication to another sink, the another sink stores a neighboring sink list received from the node, determines if a node-authenticable sink exists in its own neighboring sink list according to the authentication request, and requests re-authentication of the node to the node-authenticable sink when the node-authenticable sink exists, so that re-authentication between the node and the sink is easily performed.