Abstract: Orbital debris clouds evolution phase was defined as sphere, spheroid, rope, spiral, spreading and shell, based on the geometry shape and debris density in the evolution from the initial breakup point to the final coverage of earth. The shape character and the key drive sources were addressed in each phase. Space craft orbital mechanics theory and research method were reviewed. The evolution dynamics principle was analyzed. The separate velocity decides the shape and size during the sphere phase. Linear relative motion differential equation can be used to reduce the debris density model. Rope and spiral is distinguished from geometry, orbital maneuver theory is used to analysis the existence of pinch point and pinch line. The orbital perturbation differences of each debris in clouds eliminate the pinch region and induce the omnibearing spreading and the final figuration of the shell. The time mark between the phases was given and calculation formula was reduced and listed. The debris clouds evolution phase was visualized through computer simulation and the phase definition rationality was verified.