With the implementation of the Outline of the National Innovation-Driven Development Strategy, how to train high-quality versatile talents in recent years has become an urgent issue for Chinese higher education. Postgraduate education, as the highest level of higher education, plays a crucial role in national talent training, and cooperative teaching has emerged as the times require. This paper first analyzed the differences between the theoretical and practical reality of studying inter-school joint training. Under the introduction of traditional and diverse joint training modes, a unique new mode of joint training is proposed, that is, joint training of postgraduate students based on space-time span, which focused on the introduction from the undergraduate to postgraduate stages, taking into account the problem of "universal ease" and the imbalance of resources between universities. The dual role of "undergraduate" to "postgraduate" and "postgraduate" to "postgraduate" emphasized the growth of students under the transfer of time and space. In addition, further thoughts were made on the status quo in inter-school cooperation.