Catering to the public nature of Ad hoc network in open channel and data communication being easily eavesdropped,this paper proposed an antieavesdropping algorithm which is based on network coding.The algorithm is based on the RSA signature algorithm introducing the timestamp and homomorphic mechanism to detect tampering and replay attacks,as the basis for calculating safety,being used as one of measurement indicators in router by node safety to establish t pieces of routing entry.It generates encoding vectors by introducing the random number when the source node is encoded and the random number will be divided into n pieces.As long as the sink node receives t pieces of fragments,we can restore the original encoding vector and decode it.If the eavesdropper wiretaps are less than t,they can not get any meaningful information.It is designed for increasing the number of linearly independent coded packets.It can improve the decoding efficiency by adopting generational grouping strategy while being encoded.Simulation and theoretical analysis shows that the anti-eavesdropping algorithm based on network coding improves network performance and security by coding gain. Catering to the public nature of Ad hoc network in open channel and data communication being easily eavesdropped, this paper proposed an antieavesdropping algorithm which is based on network coding. Algorithm based on the RSA signature algorithm introducing the timestamp and homomorphic mechanism to detect tampering and replay attacks, as the basis for calculating safety, being used as one of the measurement of indicators in router by node safety to establish t pieces of routing entry .It generates encoding vectors by introducing the random number when the source node is encoded and the random number As long as the sink node receives t pieces of fragments, we can restore the original encoding vector and decode it.If the eavesdropper wiretaps are less than t, they can not get any any meaningful information. It is designed for increasing the number of linearly independent packets. It can improve the decoding efficiency by adopting generational grouping strategy whi le being encoded. Simulation and theoretical analysis shows that the anti-eavesdropping algorithm based on network coding improves network performance and security by coding gain.