The paper introduced the process of developing a new kind of soft complex stab-resistant body armor,including choosing of materials,fabric making, development of test instruments and evaluation methods.The principle of stab-resistance of the body armor was investigated by means of the finite element stabresistant model and quasi-static stab-resistant tests.The results of experiments show that the centralizing high strength fibers around the place against the edge of knife is an effective approach to the enhancement of the stab-resistance,and the soft composite stab-resistant body armor made by alternating non-woven layer and plain weave fabric layer of untwist fine denier UHMWPE can achieve a good stab-resistant performance,and it is fit in medium-thickness and light in weight,and has improved softness and comfortableness.