In this study,porous hollow fiber membranes were prepared by dry process [1].Dry process consists of three steps; first extrusion,second annealing and finally stretching.We spun hollow fiber precursors using semi crystalline polymer,such as polyethylene (PE) and polypropylene (PP) [2].The PP was supplied by Lotte chemical Co.,Korea,and was used without any purification.The fiber precursors were extruded through a single screw extruder equipped with tube-in-orifice structure spinneret at 190 oC.Nitrogen was injected through the spinneret during the spinning for hollow formation.Fiber precursor can be successfully obtained for the controlled take-up speeds.The fiber precursors were annealed in oven.The annealing temperature was set at 100 oC,120 oC and 140 oC.Stretching of annealed fiber precursor carried out cold and hot processes.Fiber precursors were stretched from 50 % to 350 % by 50 % increments.DSC was used to measure the melting point and heat of fusion of the sample at a heating rate of 30 oC/min under the nitrogen gas purge.And we determined the non-isothermal crystallization behaviors.Crystallinitiy (Xc) was calculated using the follow equation [1]: