Abstract: This paper studied the key properties of super absorbent fiber（SAF）such as linear density. Breading strength and elongation rate, modality of surface, water absorbent ratio, etc. The experimental results show that SAF has excellent water absorbability, it can absorb water more than 120 times of the fiber′s weight (>120 g/g) and the swelled fiber still keeps fiber-gel state after absorption,so it′s fit to develop the liquid absorbent materials. But SAF has circle shape of cross section and smooth surface and on crimp, its breaking strength (<0.8 cN/dtex) and elongation rate (<5.5%) are not only low but high variance. These means the mechanical properties of SAF are poor, it′s very difficult to develop products by way of using pure SAF. It′s need to blend with other fibers to develop the liquid absorbent materials of using SAF.