Purpose　This　work　exploits　virtual　reality　technique　to　analyse　and　optimize　the　preoperative　planning　of　freehand　external　ventricular　drain　(EVD)　insertion.　Based　on　the　three-dimensional　(3D)　virtual　brain　models,　neurosurgeons　can　directly　observe　the　anatomical　landmarks　and　complete　the　simulated　EVD　insertion.　Simulation　data　is　used　to　optimize　preoperative　planning　parameters　to　ensure　the　surgical　performance.　Methods　We　used　the　computed　tomography　(CT)　scans　to　construct　the　3D　virtual　brain　models.　A　group　of　EVD　insertions　were　simulated　by　inserting　virtual　catheters　at　different　entry　points.　The　key　parameters　including　the　location　of　entry　point,　the　catheter　orientation,　the　catheter　tip　position　on　lateral　ventricles,　and　the　insertion　depth　were　recorded.　A　data　analysis　method　was　then　applied　to　optimize　these　parameters,　resulting　in　the　optimal　parameters　for　the　EVD　insertion.　Results　When　the　lateral　distance　of　entry　point　ranged　from　2.5　to　3　cm,　the　success　rate　of　204　cases　was　97.79%,　which　was　higher　than　that　of　the　classic　method　(59.52%).　The　optimal　insertion　angle　towards　the　sagittal　plane　ranged　from　10.46　degrees　to　12.73　degrees.　To　prevent　penetrating　the　lateral　ventricles,　the　insertion　depth　was　optimized　to　be　3.28　to　4.58　cm.　Conclusions　The　proposed　data　analysis　method　is　helpful　to　optimize　the　key　parameters　of　the　preoperative　planning,　and　provides　useful　references　for　neurosurgeons　to　perform　the　freehand　EVD　insertion.　The　EVD　insertion　experiments　on　3D　printing　model　had　a　success　rate　of　93.75%,　which　verified　the　effectiveness　of　the　data　analysis.