运用体外法探讨了七星剑花茎凝胶和茎多糖的保湿性能，并对比了七星剑花茎多糖与胶原蛋白、尿囊素、海藻多糖和透明质酸钠等四种常用保湿剂的保湿性能，研究结果表明：在高湿度和低湿度环境下，30%七星剑花茎凝胶溶液的保湿率均高于七星剑花茎多糖和其他测试浓度七星剑花茎凝胶溶液的保湿率(MR)；75%湿度环境下，48 h保湿率大小顺序为：MR30%七星剑花茎凝胶溶液 > MR海藻多糖 > MR尿囊素 > MR透明质酸钠 > MR七星剑花茎多糖 > MR胶原蛋白；43%湿度，48 h保湿率大小顺序为MA胶原蛋白 > MR30%七星剑花茎凝胶溶液 > MR七星剑花茎多糖 > MR尿囊素 > MR海藻多糖 > MR透明质酸钠；测试范围内，30%七星剑花茎凝胶溶液和七星剑花茎多糖与化妆品常用保湿剂的保湿性能差异不大，具有很好的开发和应用前景。 The moisturizing performance of gel and polysaccharide extracted from the stem of Hylocereus undalatus Britt (PSHU) was studied by in vitro methods, and that of collagen, allantoin, seaweed polysaccharides and sodium hyaluronate was also tested as contrasts. The results show that in high and low humidity environments, the moisture retention rate (MR) of 30% stem gel solution of Hylocereus undatus is higher than that of other tested concentrations’ gel solution and PSHU. The MR ranking in 48 hours and in humidity circumstance of 75% is MR30% stem gel solution > MRseaweed polysaccharides > MRallantoin > MRsodium hyaluronate > MRPSHU > MRcollagen, and the ranking in the humidity circumstance of 43% is MRcollagen > MR30% stem gel solution > MRPSHU > MRallantoin > MRseaweed polysaccharides > MRsodium hyaluronate. Within the test range, there is little difference between the moisturizing performance of 30% stem gel solution, PSHU and other moisturizing agents commonly used in cosmetics, suggesting a good prospect of development and application of gel and polysaccharide from the stem of Hylocereus undalatus Britt used in cosmetics.