Abstract: Because the interaction in the existing virtual assembly systems is featured with machine-centered explicit interaction, the machine can not effectively perceive the user’s intentions, which leads to a higher level of the user’s cognitive load and operational burden. In order to improve the intelligence, implicit human-computer interaction was introduced into the virtual assembly system, and an algorithm of user’s intention perception based on the scene task was proposed in this paper. Firstly, explicit interactive knowledge database and implicit interactive knowledge database were constructed respectively based on the scene knowledge model and the user knowledge model. Then the user’s explicit operational intentions and implicit operational intentions were deduced by expert system. Finally man-machine opposite movement algorithms were proposed in two scenarios. On the one hand, scene could move actively close to the user when human hand was moving towards the target position. On the other hand, the object could rotate actively when hu-man hand was grasping or releasing the object. Experimental results showed that the proposed algorithm achieved human-computer cooperative interaction and reduced the user’s operational burden and cognitive burden.