On the basis of observing and analyzing the data of evolution of meandering rivers, the process of river evolution was studied from macroscopic view in generalized condition. It is discovered that a river occurs to waver along a river axis at initial stage, then the axis bends gradually;due to Coriolis Force action, the center of curvature is usually located at the south side of the river and the bending reach of south side develops quicker than its north side;as a result, the bending radius of axis reduces and wavering extent increases, thus the typical evolution process must be developed gradually from straight stream→tiny bending river→meandering river and to cut-off finally.