The invention relates to the technical field of electric power industry information web page tamper prevention, in particular to a web page tamper prevention device based on web server cache matching and a method of the device. According to the web page tamper prevention device based on web server cache matching, a feature value of a suspected Trojan program in an IP response message is extracted, whether the feature value is matched with a black list database or not is judged through fuzzy matching, then the feature values of all information of an accessed web page are extracted to be precisely matched with web server cache data, and whether a web page accessed by a client side is tampered or not is judged. Fuzzy matching processing is carried out through a first detection module, the Trojan program and other malicious programs in the web page are detected, precise matching processing is carried out through a second detection module, the feature values of all the information of the accessed web page are compared with the web server cache data, the problem that existing web page tamper detection efficiency is low is solved, the web page can be effectively prevented from being tampered by a blacker, and website safety is greatly improved.