This paper has analyzed the build-in mouse interactive function of Java3D to solve the problem that user cannot pick the objects which are too closed to each other accurately. A solution is proposed. First, a ray can be built that connects the viewpoint and the mouse point in the imageplate as the mouse is moved. Then, the ray can be checked if it intersects with any object. If yes, we can return to the object intersecting the ray and closest to the viewpoint. Finally, we can add an animation effect on the node to remind the user that this node is a pre-selected node. This paper focuses on explaining the realizing process of this method. In the final part, a practical application verifies that this method can facilitate the user in mouse picking effect- tively.