Based on the surface shape reconstruction algorithm for slope detection in combination with the calibration results of the guideway pointing errors, the influence of the sources of these errors on the actual test results is analyzed and the corresponding numerical simulation and compensation are conducted for the theoretical analysis. The results show that the wavefront testing technique method based on the scanning Hartmann principle is not sensitive to the high-frequency errors, and the wavefront testing accuracy can be improved by fitting to the low-frequency errors. This finding has an important guiding significance in the engineering application of wavefront testing technique.