Routing security is always a weak point for ad hoc network. From the point of view of the attack's impact on the network performance, the paper introduces a new analysis of routing attacks and then analyzes the incentive factors of attacks. Based on them, we present a new secure enhancement scheme (SES), which mainly takes into account both the distribution of possible existing attacks and future potential attacks? possibility .. and brings forward a new metric for routing. Experiments illustrate that SES is robust and scalable in improving routing protocols performance facing attacks and has better future application.