With the development of positive psychology theory, the cultivation of positive psychological quality of primary school students has become an important direction of mental health education. Through literature analysis, this paper systematically sorts out the connotation characteristics of positive psychological quality, analyzes the practical dilemma faced by the cultivation of positive psychological quality of primary school students, and proposes optimization strategies from the perspective of school, family and social collaboration. It is found that the construction of a threein- one training system of “curriculum intervention, environment creation, and home-school linkage” has significant value for promoting the mental health development of primary school students, and provides a theoretical reference for educational practice.