The utility model discloses a bi -polar grounding test SF6 switch mechanical characteristic's detecting system belongs to power equipment technical field, and detecting system includes switch characteristic tester, rotates the circulator that tests the speed of locating fixed connection with the switch, and the output and the switch control box of the circulator that tests the speed are connected,switch characteristic tester be bi -polar earthing switch characteristic tester, the circulator that tests the speed is the wireless circulator that tests the speed. Under the condition of disconnectground wire not, can required test time and the rotation angle of while testing switch separating brake, precision measurement, test repeatability can be good, and bi -polar earthing switch characteristic tester has saved the process of contactting in many ways, has practiced thrift operating time, has saved the work of demolising the earth connection, has improved the site security coefficient,has simplified experiment process. The measuring error that original test lead contact failure brought has been eliminated to the wireless circulator that tests the speed, greatly reduced experimentalrepetitive rate, need not install traditional circulator moreover, avoided mechanical injury.