Multi-activate bypass valve  is installed on MWD, rotary steering, turbine, downhole motor, ipper of coring tool. Before going down the well, observing the bypass hole to determine if the initial state of the tool is in the bypass "close". On the one hand, the tool state is judged by the number of pitches in using. On the other hand, the tool state can be judged by the variation of riser pressure at the same displacement.