It　is　difficult　to　grasp　and　assemble　multi-part　small　objects　in　virtual　assembly.　How　to　grasp　and　assemble　parts　quickly　and　accurately　is　an　important　part　of　virtual　reality　assembly.　In　this　paper,　a　high-precision　object　model　is　obtained　by　using　linear　laser　scanning　technology.　Leap　Motion　controller　and　mesh　collision　detection　technology　are　used　to　improve　the　accuracy　of　collision　detection.　Finally,　a　virtual　assembly　system　of　a　pop　gun　is　developed　to　achieve　a　strong　immersive　virtual　assembly　effect.