The present invention discloses a track geometry detection system track gauge calibrator. The calibrator comprises a fixed seat (1) configured to fixedly connect with a steel rail (6); a moving gaugeblock (3) comprising a vertical plate (31) and a panel (32), wherein the outer side face of the vertical plate (31) is in parallel to a plane where a Y axis and a Z axis are located, and the upper surface of the panel (32) is in parallel to a plane where an X axis and the Y axis are located; and a multi-dimensional regulation module (2) connected with the fixed seat (1) and the moving gauge block(3) and configured to regulate positions of the moving gauge block (3) in the X-axis and Z-axis directions. The tack geometry detection system track gauge calibrator can accurately regulate the positions of the moving gauge block (3) in the X-axis and Z-axis directions so as to reduce the requirements of track gauge calibration operation for personnel, save time for technicists, save manpower andsave the cost.