A free－falling body in the northern hemisphere will drift not only to the eastbut also to the south assuing that the angular velocity ω of rotation of the earth is constant，the precise value of a free－falling body s southward and eastward drift in northern hemispherecan be drawn from Newtonian dynamical equation.

By using Matlab software programming,the value of eastward drift of a falling body is calculated in the condition of air resistance.

In this article,first solving the problem of the eastward deflection of a falling object is using series for vector to obtain accurate expression for the moving equation of a falling object which the earth s revolution about its axle is considered.

Special terrain and different atmospher general circualtion system,brought up the gale of Laofengkou Area,especially eastern gale.