中文摘要：

公私合作（PPP）被认为是通过公共部门和私人部门合作来提升公共服务水平的重要模式。在PPP合作中，信任作为一种重要的合作关系规范，直接影响到合作效果，同时合作方所面临的环境不确定性和合作方行为的不确定性这两方面的外在因素会对信任-合作效果之间的关系起到相应的调节作用。在此理论假设的基础上，对中国背景下高科技生物制药行业PPP合作进行实证研究，研究表明，合作方之间的信任确实会增强合作效果，然而外部环境的不确定性会弱化信任-合作效果之间的正向关系，合作伙伴方行为的不确定性会强化信任-合作效果之间的正向关系。

英文摘要：

Public-Private Partnerships （PPP） are considered to be an important method to upgrade the standards of public services through the collaboration between public and private sectors. This research points out that during the process of PPP, trust as an important relational norms of collaboration, will have direct influence on the collaboration effects. Furthermore, environment uncertainty and the partner＇s behavior uncertainty that the partners have to encounter will accommodate this kind of relationship. Based on these theoretical hypothesis, the research did the empirical studies under the background of China＇s PPP collaboration in medical and health fields, the resuhs show that the trust between the partners can enhance the collaboration effects, however, the environment uncertainty will weaken the positive relation between trust and collaboration effects, while the partner＇s behavior uncertainty will strengthen the positive relation between trust and collaboration effects. This study is not only having a significant theory value, but also has some practical guidance for cross-sector cooperation.