Abstract: Taking relational governance as theoretical basis, introducing cooperation as a mediating variable,and based on the analysis of the questionnaire collected from 129 owners and contractors in China, we found that competence trust and integrity trust have positive roles in promoting improvement of construction project management performance, and cooperation is the partial mediating factor between those two kinds of trust and construction project management performance. The relationship between institutional trust and cooperation and construction project management performance is not significant. Based on the conclusions above, we propose that promoting the reputation of information publishing platform, optimizing the tender documents and improving project communication mechanisms can be used as the main way to motivate trust and cooperation between the two sides in contract projects, and ultimately improve project management performance.