With the background of collaborative 3D-CAD design, the paper probes into the detection of the conflict in the real-time collaborative design, and presents an idea that data confliction in real-time collaborative 3D design is entity feature confliction. According to this idea, the paper discusses the conflict detection methods based on feature. By analyzing the shortcomings of the methods, the paper provides a geometry level conflict detection strategy with higher feasibility as well as its timing sequence scheme. The conflict detection data structure and conflict detection rules are also studied. This conflict detection idea has been validated in the Pro/ENGINEER platform of PTC Corporation and a better conflict detection result is achieved.