In order to solve the problems of low efficiency of traditional manual method and low adaptability of single-line laser measurement in tire tread depth measurement, a set of tire tread depth measurement method based on multi-line laser is proposed in this paper. This method obtains the images of tire with a multi-line laser stripe by measuring device. Three-dimensional point data of the center point of the laser stripe on the tire surface is obtained by the triangulation technique, and the tire groove points and tire tread points are screened out from the 3D point cloud data. The tire groove points are synthesized into a curved surface, the distances between the tire pastry and the groove surface are successively calculated, and the depth of each groove is obtained to determine the wear condition of the tire. The difference between the measured results and the depth gauge is less than 0.1 mm, which can meet the requirements of tire tread depth measurement.