Polypropylene superfine fibers or cell porous fibers were prepared from the Bi-component blend fibers of polypropylene/easy hydrolytic degradation polyester (PP/ EHDPET, by alkaline hydrolysis process. EHDPET is a kind of copolyester that can be rapidly hydro-degraded in the hot alkaline solution. This article discusses the kinetics of alkaline hydrolysis of EHDPET, and the effect of catalyst, bulk ratio, and the content of PP-grafted maleic anhydride on the alkaline hydrolysis process. Meanwhile, the morphological change of the outer surface of blend fibers during this process was also investigated by the technology of scanning electron microscope.