The invention relates to a game anti-cheating method and a game anti-cheating system based on a block chain. The method comprises the following steps: acquiring user historical behavior data, collected in advance, of a game application; acquiring user current behavior data, collected in real time, of the game application; according to the user historical behavior data, the user current behavior data, and a cheating determination rule of the game application, determining a cheating situation of a user current behavior is determined; and storing a cheating determination result, the user currentbehavior data, and the user historical behavior data on the block chain as user credit data. According to the method provided by the invention, the block chain is used as a credit center to store theuser credit data containing a user cheating judgment result, and the user credit data can be used to actively make restriction measures to users with cheating behaviors, thereby fundamentally preventing game cheating behaviors, having a wide defense range and a good effect, and not affecting client experience. In addition, the user credit data is stored on the block chain, and is safe from tampering, thereby ensuring authenticity and effectiveness of the data.