Abstract: Considering influences of installation error，support conditions and gear load deformation，a new method based on finite element method for calculating system error of involute helical gearbox was studied.Using gear space meshing theory，systematic error and human error of each gear pair were obtained，and calculation formula of gear comprehensive error was given.Building a real involute helical gear intersecting interference gear pair model，the tooth profile stress change of gear and distribution of tooth contact area were compared and analyzed based on standard gear and intersecting interference gear.Calculation results showed that contact stress of point contact and line contact increased when gear pair considered installation error.Line contact state only changed by 10.8%，and contact stress point-line contact changed by 46.4%.It was indicated that helical gear point-line contact was more sensitive to gear comprehensive error than line contact.