As to product design itself has quite complexity and many domain influence factors are integrated in concurrent design (CD), conflict phenomena exists in any process of carrying out CD. Conflict elimination is an important key to carrying out CD effectively. Conflict usually relates to many members in multifunction group of CD. Negotiation that is a process of multiple iteration and repeated alternation is utilized in CD conflict elimination. Many objects and constraints are considered in the process of negotiation and it is very hard to have no problem in the process of calculation, reasoning, evaluation and decisionmaking. As to the updating error is a tracing process and a lot of work done before is needed to repeat, efficiency of conflict elimination is very low. In this paper, a method of conflict elimination of product CD based on blackboard model is put forward. Design conflict producing, system and mechanism of conflict elimination based on blackboard model are analyzed and described. It takes gear CD conflict elimination as an example to illustrate the concrete application of the method and system.