Abstract: As a polymer with excellent mechanical strength, heat resistance ability and chemical stability, poly(vinylidene fluoride) (PVDF) was used to prepare microporous membrane for lithium battery through melt extrusion and post draw. A row-nucleated lamellar crystalline structure was achieved by adjusting the draw ratio during the process. The investigation results indicated that the casting film was highly orientated along the flowing direction. It is hard for cast film to gain a proper porous structure at room temperature stretching due to short relaxation time of PVDF, even if the cast film achieved the row-nucleated lamellar structure. Based on the time-temperature equivalence principle, the reduction of cold-drawing temperature can lead to the same effect by increasing relaxation time. More plastic deformation was generated in the amorphous region when the cast film was drawn at a low temperature below room temperature. By comparing the SEM images of the film drawn at different temperature, it was observed that the film cold-drawn at low temperatures exhibited much better porous structure and pore-size distribution. The formation mechanisms of microporous structure at low-temperature cold draw were also discussed.