To address the problem of extracting perception information difficultly in making intelligent digital role, we propose the concept of differential according perception and according to it design a perception model based on the snake. A new process of pretreatment of information has been inserted between obtaining information and information processing, which will inosculate all input information. The pretreatment relies on the mathematic model of artificial neural net, which could better reconstruct the object focused by digital role with the differential information. The intelligent role designed with our policy has faster real-time response, and can finish the task accurately.