In the previous textbooks of gravitational prospecting, the computation of gravity emendation values arising from mass of the Earth's crust at the distance over 2 km from the observation point is confined only to an area of circular ring 2.0~166.7 km in breadth and the computation expressions coming into existence in the orthogonal coordinate system are adopted. China Geological Survey has generalized in recent years the computation program of gravity emendation value that adopts the computation expressions both in the orthogonal coordinate system and in the spherical coordinate system; nevertheless, the computation of gravity emendation values remains confined to an area of circular ring 2.0~166.7 km in breadth and fails to take into account the gravitation arising from mass of the Earth's crust at the distance over 166.7 km from the observation point.10 years ago, the authors deduced alone gravity expression of the hexahedron with a spherical crust form and other expressions related to the computation of gravity emendation values. After this, adopting these expressions, the authors conducted researches on high precision computation and numerical value characteristics of gravity emendation values arising from mass of the Earth's crust in pure spherical coordinate system, with the following computation achievements obtained: ① high precision computation result of "Gravity Emendation Value arising from Mass of the Earth's Crust at Distance Over 169 km From Observation Point" (GEVMECDO 169 km FOP) at the square grid 40 km in breadth on whole Earth's land and ocean surface; ② high precision computation achievements of GEVMECDO 169 km FOP at longitude and latitude grid of China's continent; ③ high precision computation achievements of GEVMECDO 169km FOP at the square grid 0.556km in breadth in local 3°×2° area along the large curved portion of the Yarlung Zang Zangbo River.Based on analyzing numerical values distribution characteristics of GEVMECDO 169 km FOP on the whole Earth's and local surfaces, the authors have arrived at the following conclusions d: ① The maximum, minimum and mean values of gravity emendation values on the whole Earth's surface are 106.990 mgal (87.877°E, 32.271°N), -41.146 mgal (166.122°E,28.327°N) and -16.439 mGal respectively; the distribution characteristics of these values are in the main consistent with the distribution characteristics of the Earth's land altitude/sea depth values. ② The distribution characteristics of gravity terrain emendation values in a local area arising from mass of the Earth's crust in large circular rings 169-1 272 km in breadth are in the main consistent with the distribution characteristics of land altitude values in this local area. These data suggest that there are high frequency components in gravity emendation values of the area with larger altitude differences,and these high frequency components with terrain altitude values have positive correlation. These facts differ remarkably from the opinions put forward by many researchers. In fact, these high frequency components result from larger altitude differences of neighboring points in a local area. ③ No mater how large the differences of altitudes /sea depths in a local area and its peripheries are, these GEVMCDO 1 272 km FOP are approximately close to a very small constant and may not be computed; ④ Where the altitude or sea depth of local area and its peripheries changes smoothly, the gravity emendation values of the whole mass of the crust over the distance of 169km are approximately close to a constant and hence may not be calculated. The results achieved by the authors have important significance for perfecting high precision computation of gravity emendation values arising from mass of the Earth's crust. The authors suggest introducing these achievements into new textbooks of gravitational prospecting and also propose to study and extend this research topic with high precision and high speed with the purpose of convenient application of gravity emendation values arising from mass of the Earth's crust on the basis of these achievements.