Abstract: In order to study the differences in the quality of Sapindus mukorossi leaves which collected in different time,and make sure the best harvest time.The leaves were collected in Dushan,Guizhou on March 15 and in the nursery lands of Guizhou Academy of Forestry,Guizhou on April 5.The contents of Sapindus mukorossi water,water extracts,total ash,polyphenolic constituents,free amino acids and caffeine were determined and analyzed,the average content of water was 6.65%,water extracts was 39.26%,free amino acids was 6.30%,total ash was 9.36%,caffeine was 0.048% and polyphenolic constituents was 5.28%.There were some difference in leaves quality that collected in different time.To evaluate the Sapindus mukorossi leaves by membership function,the leaves that collected before Qingming festival had better quality than that collected after Qingming festival,no matter where the leaves come from.Compared the contents with other tea,the water extracts,amino acids were closed to the good tea.The best collected time was determined by compared and analyzed,it can provide some data for developing Sapindus mukorossi.

Key words: Sapindus mukorossi, main components, quality evaluation, membership function