The five-stage model of plate breakup can explain the linear characteristics of rift valleys and oceanic ridges, which other hypotheses in terms of mantle convection, hot-spots and mantle plumes cannot be explained. The course of the plate breakup is as follows: any plate has to undergo 5 stages before breaking up; the 5 stages own each tectonic system; the strikes of these 5 tectonic systems gradually deflect 15° towards the rotation axis of the Earth; and after entering the 5th stage, the plate will normally be broken up. This model is supported by experiments.