The method of extracting shield tunnel lining misalignment based on point cloud data belongs to the technical field of tunnel engineering survey. By using the vertical relationship between the point cloud method vector and the tunnel section method vector, the method extracts the transverse point cloud of different loops and uses the fact whether each loop of the tunnel corresponds to the mutationof the transverse point cloud to determine the existence of misalignment in the loop, and determines the magnitude of misalignment in the loop by the size of the sudden change of the point cloud of cross section. By extracting the point clouds data on the vertical section of the corresponding angles of the two adjacent segments, the method can help to tell whether there is a sudden change in point cloud data or not in the vertical section. According to the sudden change of point cloud data, the method can help to judge the size of misalignment between two adjacent loops of the tunnel, and finally obtain the size of misalignment within each loop and the size of misalignment between two adjacent loops. The invention has the advantages of high efficiency, precision and intelligence thanks tothe use of 3-D laser point cloud data, and it can obtain the size of misalignment between loops and that within the same loop from any angle.