To solve the problem of data tampering and selective forwarding attacks in WSN, a model of multi-signature based on hash function was proposed。Nodes can find malicious nodes tampering packets though the model。As packets cannot be tampered with,the nodes can find dropping packets by forwarding controlling packets。The approach reduce the cost of energy,and can prevent collusion attack of malicious nodes。The results got in the experiment in the NS2 environment showed that the method performed very good in detection rate and error detection。