At the beginning of the change in bearing condition, the bearing fault features are weak, often drowning in the background noise. It makes difficult to extract weak fault features from the vibration signal. If the fault features cannot be effectively extracted, the diagnostic accuracy will be greatly affected. Under this background, a fault diagnosis framework including two stages of signal enhancement and intelligent fault recognition is proposed in this work. Firstly, use a genetic algorithm to obtain the optimal combination of parameters, upon which the original fault signals are decomposed into intrinsic modal function components. Then, they are transformed into the spectrum signals and inputted into the proposed Bayesian network using dynamic weighted transfer learning (DWTL). This paper uses the DWTL method to set the source domain weight factor and the balance coefficient based on data quantity in different source and target domains.The DWTL method proposed in this paper can improve the fault diagnosis accuracy and effectively avoid the negative transfer phenomenon. An example of rolling bearing fault diagnosis is conducted. The results show that the accuracy of fault diagnosis based on the proposed framework is about 10% higher than that of other fault diagnosis methods. Therefore, the validity and feasibility of the proposed fault diagnosis framework are proved.