The present invention provides a long wavelength static correction method in loess plateau seismic data well control, belonging to the field of geophysical prospecting for petroleum. The long wavelength static correction method comprises: (1) inputting a surface elevation file in the range of data processing, the file consisting of X and Y coordinates and elevation information; (2) calculating elevation smoothing parameters k and l, and performing smoothing of the inputted surface elevation file; (3) performing function fitting of the long wavelength static correction in the well control; and (4) calculating the long-period static correction. According to the invention, long-period static corrections in the loess plateau seismic data may be effectively calculated through controlling of a small amount of wells.