Aiming at ANSS( ANtivirus Software Shield) model disadvantages，this paper extends ANSS modeland proposes a new model named EANSS( Enhanced ANtivirus Software Shield) ． There are some new rules of theattack are added into the new model，and the real-time monitoring mechanism and the self learning mechanism alsobe joined in the ENASS model to improve the ability of protection． Experiment results show that the EANSS modelnot only don’t influences the operations of normal applications but also can protect antivirus software from beingterminated by them with low CPU performance overhead and memory write performance overhead．