Abstract: Efficient and precise measuring equipment is essential for ensuring both the production efficiency and quality of gears.A gear measurement model based on the distance measurement principle of a line laser sensor is established, and a seven-degree-of-freedom (7-DOF) line-laser gear measuring instrument is developed for rapid gear inspection. The instrument primarily consists of an optical vibration isolation platform, a highly flexible motion mechanism, a rotary spindle, a circular grating, and a software system. The motion mechanism, combined with the rotary spindle, realizes the required 7-DOF movements of the instrument, significantly enhancing the sensor’s pose adjustment capability. The rotary spindle is integrated with a circular grating to acquire the rotational angle in real time and to trigger the sensor for synchronous acquisition of gear flank data, thereby enabling closed-loop measurement. Furthermore, dedicated 7-DOF line-laser gear measurement and evaluation software is developed, which supports the measurement and assessment of gear profile deviation, topography deviation, and other parameters. Experimental results demonstrate that the measurement accuracy of the developed instrument shows a maximum deviation of less than 5.4 µm when compared with a commercial gear measuring center. Nine repeated experiments were carried out, and the maximum expanded uncertainty was found to be 2.0 µm.