Collaborative design is new design style to meet the increasing requirement of global market, which share various resources and information of different designers with the aim of reaching the purpose. Designers complete the same task in different places. Designers work at the same time will encounter the conflict, which is a critical problem for collaborative design. Firstly, the class of conflict is proposed to make a basis for conflict resolution, which is classified into data conflict, knowledge conflict and recourses conflict. The resolution model is constructed for collaborative design. By means of the conflict observation, conflict decision and conflict informing, conflict resolution is solved. The conflict resolution knowledge and process are described with UML. By means of algorithms, conflict resolution decision making method is present. Dead locks are danger for system. A set of dead lock resolution mechanism are provided to solve the problem. By means of a case study, the methodology is illustrated for conflict resolution.