OBJECTIVE：To establis h the fingerprint of Lonicera japonica polysaccharide，and to investigate in vitro inhibitory effect of it on respiratory syndrome virus （RSV）. METHODS ：Polysaccharide from L. japonica was prepared by water extraction and twice alcohol precipitation method. After hydrolysis with trifluoroacetic acid ，derivatization with hydroxylamine hydrochloride and pyridine ，the fingerprint was established by GC method. The determination was performed on HP- 5 capillary column ，and the detector was flame ionization detector ；the temperature of the sample inlet was 250 ℃；the temperature of the detector was 300 ℃ （programmed temperature ）；the carrier gas was nitrogen （flow rate of 50 mL/min）；split sampling was adopted （split ratio of 60∶1）；the sample size was 2.0 μL. Using rhamnose as reference substance，GC fingerprint of 12 batches of L. japonica （S1-S12） was drawn ，and the similarity evaluation was performed with Similarity Evaluation System of TCM Fingerprint （2012 edition）. Cluster analysis and principal component analysis were conducted by using SPSS 21.0 software. Using ribavirin as positive control ， half effective concentration （EC50）and treatment index （TI）as indexes ，MTT assay was used to investigate in vitro inhibitory effect of L. japonica polysaccharide on RSV. RESULTS ：There were 12 common peaks in GC fingerprint of 12 batches of L. japonica. The similarity was greater than or equal to 0.994. Seven common peaks were identified ，such as rhamnose ，arabinose， fucose，mannose，glucose，galactose，inositol hexaacetate. According to the cluster analysis ，12 batches of samples could be divided into two categories ，i.e. S 1，S7，S10 and S 11 clustered into one category ，and others clustered into one category. In principal component analysis ，the eigen values of 3 principal components were all greater than 1 （5.659，2.745，1.724 respectively），and their cumulative contribution rate was 84.400％. The comprehensive score of S 12 was the highest ，the second was S 5，and the lowest was S 11. EC 50 of total polysaccharide ，80％ alcohol precipitated polysaccharide ，50％ alcohol precipitated polysaccharide and 20％ alcohol precipitated polysaccharide of L. japonica （No. S 12） were 0.76，0.61，1.03，3.04 g/L， respectively；TI were 15.36，18.51，11.69，4.22，respectively. EC 50 of 80％ ethanol alcohol precipitated polysaccharide was the lowest，and its TI was close to that of positive control （20.08）. CONCLUSIONS ：Established fingerprint provides reference for the quality evaluation of L. japonica . L. japonica polysaccharide has a certain inhibitory activity on RSV in vitro ，and the 80％ alcohol precipitated polysaccharide has the strongest activity.