Cold-sensitive soybean (Glycisne max Zhonghuang No.22) seeds were used to investigate the effects of osmoconditioning for invigoration of seeds chilling tolerance and the changes in membrane lipid by thin layer chromatography and gas chromatography to disclose the role of membrane lipid played in imbibitional chilling resistance capacity. Results are as follows: being treated with 33% PEG6000, seeds germination index, vigor index and root dry weight presented the trend of upward as the osmocondition time prolonged. In 72 h, the percentage of unsaturated phospholipid (e.g. PC and PE) in soybean seed increased, composition of lipid fatty acid changed: the saturated fatty acid 16:0 content in PC, PE, PI significantly decreased, while unsaturated fatty acid 18:2 increased greatly, which led to increase index of unsaturation fatty acid of lipid. These changes were positively corrected with osmoconditioning time. After treated with PEG, membrane fluidity increased to provide precondition for preventing imbibitional chilling, keeping the integrity of membrane system and normal metabolism.