The present application relates to a U-shaped touch gauge, which comprises a base plate, a transfer plate, a floating column, a fixing block, a measuring sleeve, a measuring column and the like. In use, round head of top end of the floating column is in contact with bottom surface of a work piece. The floating column is compressed downward when it contacts high surface of the bottom surface of the work piece, left side of the transfer plate is depressed and then right side thereof is lifted, in the meantime, the right spring is compressed and the measuring column is lifted.