In this paper,starting with mechanical energy conservation and angle momentum conservation of a mass point in central conservative force field,kinetic energy of a mass point is divided into two parts including both radial kinetic energy and tangent kinetic energy.

The orbital stability in the central force field;

The orbit of motion in central force field is discussed and a few decision methods of the orbit stability are given.

By the natural and harmonious relationship between differential forms and differential equations and between differential forms and vector analysis, we discuss the properties, which are covariant under the transformation of coordinates in the framework of differential forms, of particle motion in a central force field.

In addition,we discussed the character of these curves and the relations between Multi-knot curve and central field.

In this paper it is shown that there are two vector constants of the motion for a charged particle in the central field of force.

In this paper,the symmetries of two central fields in the classical mechanics that result in closed orbits for all bound particles are discussed by using the group theory method.

Discussion to the Critorion of the Conservative Field;

As to a conservative field,the turning degree of the vector of the surface field is zero.

Chinese ancient closed and scattered agricultural economy that formed by Chinese special geographical conditions,is economic source of the conservative habit of the public.