[目的/意义]探讨知识贡献活动的制约因素及其作用机制，为专业虚拟社区的未来发展任务提供实证支撑。[方法/过程]通过扎根理论的部分程序抽取开放式访谈得到的制约因素，借助解释结构模型和行动者网络理论分析制约因素的作用机制。[结果/结论]18个知识贡献活动的制约因素整体上形成了一个复杂的由多级层序结构组成的动态行动者网络，涉及用户心理和状态、用户体验、系统功能与设计、信息质量以及运营机制五类行动者。专业虚拟社区需要把握未来发展任务的轻重缓解，首先解决信息质量和运营机制等关键问题。

[Purpose/significance] Exploring the constraints on knowledge contribution activities and their acting mechanism, will provide professional virtual community the empirical supports for future development tasks. [Method/process] The constraints obtained from open interviews are extracted through partial procedures of grounded theory methodology, and acting mechanism of constraints are analyzed by means of interpretative structural modeling and actor network theory. [Result/conclusion] Eighteen constraints on knowledge contribution activity form a complex dynamic actor network composed of multi-level hierarchical structure as a whole, involving five types of actors: user psychology and state, user experience, system function and design, information quality and operation mechanism. The professional virtual community needs to grasp the priorities of development tasks, and first solve key issues such as information quality and operation mechanism.