Newton's law of universal gravitation does not explain the abnormal precession of Mercury, and the values of gravitational constant G measured by different research teams does not coincide. This paper had study of the two problems from perspective of physical aesthetics and ideal fluid and derived a new formula for calculating the exact G value by using the speed of light in vacuum, which including error correction formulas and verified by experimental data of other scientists. After corrected，the G values measured by some famous surveyors approximately coincides with a specific value. The formula also verified by the precession of the perihelion of mercury , it contributes an additional 35.94"/cy to the theoretical calculation value of the precession of Mercury, then, the abnormal precession value of Mercury calculated by Le Verrier reduce to about 2"/cy, this give another explanation for the abnormal precession of Mercury which is completely different from Einsteins general theory of relativity. The preliminary Conclusions is that G equals 1/(16πc). For further verify the formulas, this paper also designed an experimental plan for the space agency to disprove Einstein's GTR.