Linear guide rail precision automatic measuring device and measuring method thereof

The invention discloses a linear guide rail precision automatic measuring device and a measuring method thereof. The device comprises a frame; a standard guide rail is fixedly installed on one end of the frame; a reference slide block is sleeved on the standard guide rail; the reference slide block is fixedly provided with a top board; the two sides in the top board width direction are each provided with an L-shaped support; the two L-shaped supports are respectively fixedly provided with vertically arranged non-contact probes; the two on-contact probes are respectively arranged at a left position and a right position in the width direction of a guide rail bottom; the frame is provided with an auxiliary guide rail parallel with the standard guide rail in terms of position; the auxiliary guide rail is provided with a movable slide block linked to the L-shaped supports; the movable slide block is linked to a driving apparatus through a belt; and the frame is also provided with a bracket bearing and holding a guide rail to be detected and a press head for pressing the end portion of the guide rail to be detected onto the end portion of the standard guide rail. By using the measuring mode, it is unnecessary to fix the guide rail to a detection platform through screws, and the measuring efficiency can be greatly improved.