Automatic measuring instrument for PXE piston

The utility model relates to the field of machining equipment, and particularly discloses an automatic measuring instrument for a PXE piston which can measure the ball top distance and the overall length in one time. The automatic measuring instrument comprise a base plate, a piston measuring seat, a first dial indicator, a second dial indicator, a first measuring plate, a second measuring plate and a third measuring plate, before measurement, the PXE piston measuring instrument uses a standard piston to measure once, when the first measuring plate and the third measuring plate rise to the highest position, the first dial indicator and the second dial indicator return to zero, in batch measurement, the first measuring plate and the third measuring plate rise to the highest position, the reading of the first dial indicator plus the ball top distance of the standard piston is the actual ball top distance of a piston that is measured, the reading of the second dial indicator plus the overall length of the standa