A rapid detection method for the geometric accuracy of the linear motion axis of an NC machine tool, uses accelerometers to measure the acceleration perpendicular to the direction of motion when the linear motion axis moves at a uniform speed. Firstly, the measuring device is mounted on the linear motion axis, and the upper measurement system automatically performs multi-channel acquisition and storage of the motion point acceleration data. Then, filter the acceleration data at the different speeds. Finally, the displacement data is obtained by quadratic integration of the filtered acceleration data in the time domain. Then calculate the straightness of the linear motion axis using the End Point Fit method, and complete the rapid measurement of the straightness of the linear motion axis of the machine tool. This can realize the rapid measurement of the geometric accuracy of the linear motion axis of the machine tool.