Method for correcting non-parallelism of normal level surface

The invention discloses a normal level surface non-parallelism correction method, which is carried out through a normal level surface non-parallelism correction system, and comprises the following steps of: measuring and calculating longitude and latitude of each elevation point in an area by arranging a GNSS (Global Navigation Satellite System) acquisition unit, and converting the longitude and latitude into geodetic elevation of each elevation point; by setting the height difference of all to-be-measured points on an attached level line formed by connecting every two elevation points with known elevations in the area, the temperature of all the to-be-measured points is acquired, and a temperature anomaly interval of the area is determined and acquired; temperature correction factors and elevation abnormal value factors of all attached level lines formed between every two elevation points with known elevations in the area are obtained through calculation based on the screened and judged temperatures, and the