The computation project and computation process for gravity correction values within the pure spherical coordinate system are expounded for the first time in this paper. All important formulae in the scheme are educed separately by the authors. The excellences of this computing scheme are as follows: ① By using observational point P as the center of the computation region and by using spherical surface distances am=am-1+Δa·bm-1(m=2,3,…,M) as the radius, the computation region is plotted out as M girdles. Then, By using Δλ0 as the angle interval of radials from P point, all girdles are plotted out as integral N parts. This scheme for plotting out the computation region is extremely precise and its computation precision is very high. ② Under the condition of complex terrain and remarkable different altitudes, the computation precision can be improved by minimizing values of Δa,b and Δλ0. ③ The gravity correction values of very large surveying area will not be confined by the 6°cingulum and the standard map sheet and can directly be computed by using altitude values with longitude and latitude.