With　the　development　of　robot　technology,　it　is　an　inevitable　trend　in　the　future　that　Robots　will　come　into　the　normal　life.　Robots　must　be　safe　enough　and　ensure　no　hazard　to　person　in　order　to　coexist　with　people　harmoniously.　This　paper　provides　a　method　to　promote　the　robot　safety　by　taking　position-torque-position　switching　control.　Namely,　robot　will　work　in　normal　position　control　mode　for　fast　and　accurate　respond,　until　it　impacts　to　humans.　Once　robot　strikes　to　humans,　it　will　change　to　torque　control　mode　from　position　mode　immediately.　Robot　will　contact　with　humans　very　softly　in　torque　control　mode,　so　it　is　very　safe.　When　humans　leave　from　robot,　it　resumes　to　position　control　mode,　and　executes　remainder　tasks.　Signal　of　striking　to　humans　can　be　detected　by　torque　sensor　fixed　in　joint　axis.　Withdrawing　of　humans　can　be　detected　by　measuring　robot　speed　variety.　The　merit　of　above　control　method　is　that,　at　the　condition　of　ensuring　normal　task　performance,　the　robot　safety　has　been　enhanced　remarkably.　This　method　has　been　experimented　at　a　IDOF　robot　arm,　and　gain　the　anticipate　results.