Three-wide education requires continuous improvement of the pertinence and effectiveness of talent training through all employees, the whole process, and all-round measures and paths. Interdisciplinary postgraduates have obvious characteristics. After analysis, it is found that turning disadvantages into strengths is a breakthrough to improve the quality of scientific research, but there is a huge gap between their advantages and disadvantages. How to make up for this gap is the key to solve the problem. Based on the idea of three-wide education, the cultivation mechanism for interdisciplinary postgraduate has been constructed, including the realization of "full-staff education" through the "four into one" system, realization of full-process education through the whole process and key links of the cultivation, realization of all-round education through the joint efforts.