Though security protocols in mobile ad hoc networks are becoming widely studied, only a few issues have been developed from the point of view in the attack's impacts on the network performance. We firstly analyze some attacks in the context of secure routing protocols and then investigate their incentive factors in detail. Based on the description of distribution of possible existing attacks and future potential attacks? possibility, we present a new secure enhancement mechanism (SEM) and introduce the whole process of its implementation. We also provide some presentations of certain functions about extension route table. Simulation results confirm the robustness and scalability of SEM in improving routing protocols performance and demonstrate its superiority in future application.