OBJECTIVE：To establis h the UPLC fingerprint of Poria co cos aqueous extract ，and to investigate its relationship with sedative and hypnotic effect. METHODS ：Ten batches of P. cocos from different areas were extracted with water to obtain the aqueous extract. UPLC method was adopted. The determination was performed on Waters HSS-C 18 column with mobile phase consisted of 0.1％ phosphoric acid solution-acetonitrile-methanol （gradient elution ） at the flow rate of 0.4-0.2 mL/min. The detection wavelengths were set at 210 and 242 nm. The column temperature was 40 ℃，and sample size was 2 μL. The fingerprints of 10 batches of P. cocos aqueous extracts were established by using the Similarity Evaluation System of TCM Fingerprint （2012A version），and the common peaks were identified. The sedative and hypnotic effects of 10 batches of P. cocos aqueous extracts from different areas under the synergistic action of pentobarbital sodium were investigated by taking the sleeping rate ，sleep latency and sleep duration of mice as the single efficacy index. After data transformation of single efficacy index and total efficacy （single indexes calculated by analytic hierarchy process ），grey correlation analysis was used to analyze the correlation between the common peaks in fingerprint of P. cocos aqueous extract and the single efficacy index and total efficacy. RESULTS ：There were 24 common peaks in 10 batches of aqueous extract of P. cocos ， and 11 components were identified ， i.e. 16 α-hydroxydehydrotrametenolic acid （peak 6），16α-hydroxytrametendic acid （peak 7），poricoic acid B （peak 9），dehydrotumulosic acid（peak 10），poricoic acid A （peak 12），polyporenic acid C （peak 15），3-O-acetyl-16α-hydroxydehydrotrametenolic acid （peak 17），dehydropachymic acid （peak 20），pachymic acid （peak 21），dehydrotrametenolic acid （peak 22），dehydroeburicoic acid （peak 24）. Grey correlation analysis showed ，the correlation between 24 peaks and sleep duration was greater than 0.6（0.611 5- 0.811 8）；the correlation between 24 peaks and sleep latency was greater than 0.6（0.605 9-0.790 4），except for peaks 14，24 and 2；the correlation of 24 peaks between sleeping rate was greater than 0.6（0.606 4-0.721 6），except for peaks 23，19，17 and 5； the correlation of 24 peaks between total efficacy was greater than 0.6（0.619 0-0.781 2），except for peaks 2，5，19. The top 10 chromatographic peaks related to the total efficacy were peak 15（polyporenic acid C ），peak 16，peak 8，peak 11，peak 12 （poricoic acid A ）， peak 1， peak 7 （16 α-hydroxytrametendicacid）， peak 3， peak 9 （poricoic acid B ） and peak 20 （dehydropachymic acid ）. CONCLUSIONS ：UPLC fingerprint of P. cocos aqueous extract was established and 11 components were identified. Ten components such as polyporus acid C are closely related to the total efficacy of sedation and hypnosis ，which preliminarily reveal the material basis of the sedative and hypnotic effect of P. cocos .