The invention provides a virtual assembly-oriented collision detection method based on an AABB (Axis Aligned Bounding Box)-OBB (Oriented Bounding Box) mixed bounding box. A pre-processing stage comprises the following steps of: splitting a model of a deformable object, establishing an OBB layered binary tree layer by layer, and establishing an AABB of the entire model. A real-time stage comprises the following steps of: maintaining the AABB at the peak of the binary tree, and carrying out rough collision detection on the entire model; maintaining an OBB at the other nodes, and carrying out accurate collision detection by using the OBB; and finally, carrying out patch-level collision detection. The method comprises the following steps of: loading a three-dimensional model; splitting the model, and establishing a layered binary tree; carrying out collision detection by using the AABB in the rough collision detection stage; carrying out collision detection by using the OBB in the accurate collision detection stage; and finally, carrying out patch-level collision detection. The method provided by the invention can ensure that in an aircraft engine assembling process, a spherical nut wrench is used for disassembling and assembling spherical nuts, and an internal hexagonal wrench is used for disassembling and assembling plug screws.