Abstract: The black hole attack is the main kind of attacks against AODV protocol in an Ad hoc network, black hole attack is a black hole node spoofing a legitimate node by changing the serial number or hop count, thereby drop the received packets, a much more threat by a joint attack of multiple black holes. This paper proposes an authentication chain mechanism based on the secure recursive function to overcome the black hole attack, by which the successive nodes of a route are unified only on the deterministic state transition relation of the recursive function to implement a unique association for security so that the whole route form an authentication chain. With the mechanism of this paper, even if the pseudo-random linear sequence as a kind of simple recursive function is adopted, as long as its linear complexity is greater than the number of nodes in the authenticating chain so that the attacker cannot obtain continuous state values of more than two times the linear complexity of the sequence, and then the secure authentication of the route can be guaranteed. Therefore, the mechanism and method presented in this paper is a novel and effective method to defend against the black hole attack.