The invention provides a 3D printer fault detection method, which particularly aims at a temperature aspect, solving the problem in the prior art that 3D printer fault detection is lack of repeated effect. With the adoption of the method, the complicated application requirements can be met by the sensitivity and control flexibility of a 3D printer under situations that temperature difference is relatively small and control requirements are precise when the 3D printer is used for producing fused materials such as the situations of medical device products and complex type workpieces.