The study of mantle distribution does relate to the reflecting of seismic waves, and has important meaning. Using Archimedes Principle of Sink or Buoyancy (APSB), Newton’s gravitation, buoyancy, lateral buoyancy, centrifugal force and the Principle of Minimum Potential Energy (PMPE), we derive equation of static mantle density distribution. It is a set of double-integral equations of Volterra/Fredholm type. Some new results are: (1) The mantle is divorced into sink zone, neural zone and buoyed zone. The sink zone is located in a region with boundaries of a inclined line, with angle α1=35°15’ apex at 0(0,0,0) revolving around the z-axis, inside the crust involving the equator. The buoyed zone is located in the remainder part, inside the crust involving poles. The neural zone is the boundary between the buoyed and sink zones. The shape of core (in sink zone) is not a sphere. (2) The Potential energy inside the Earth is calculated by Newton’s gravity, buoyancy, centrifugal force and lateral buoyancy. (3) The gravitational acceleration above/on the crust is tested by formula with two parameters reflecting gravity and centrifugal force, and the phenomenon of “heavier substance sinks down in vertical direction due to attraction force, and moves towards to edges in horizontal direction due to centrifugal force” is tested by a cup of stirring coffee.