Collaborative editing has become one of the most popular forms of knowledge contribution in virtual communities. Wikipedia— the largest online encyclopaedia— is a representative example of collaborative work. Despite the abundant researches on Wikipedia, to the best of our knowledge, no one has considered the integration of social capital and conflict. Besides, extant literatures on knowledge quality just pay attention to task conflict, while relational conflict is rarely mentioned. Meanwhile, our study proposes the nonlinear relationship between task conflict and knowledge quality instead of linear relationships in prior studies. We also postulate the moderating effect of task complexity. Furthermore, there is little empirical research on the influence of social capital on conflict, especially the distinct effects of cognitive and relational capital. This paper aims at proposing a theoretical model to examine the effect of social capital and conflict, meanwhile taking the task complexity into account. We will make our efforts to verify our research model in the following phases, and we believe that the present work can make some contributions to both research and practice.