Abstract: In order to study the changes of the quality and their optimal harvest period of the Cabernet Sauvignon grapes in Xinjiang,the Cabernet Sauvignon grape was tested in four habitats of Hami,Changji,Heshuo and Yili. The quality of Cabernet Sauvignon fruit was measured at different harvesting periods,and principal component analysis was used to analyze the differences in the quality of Cabernet Sauvignon and the indexes harvest time in each producing area. The results showed that the fruit pH value,100-grain weigh,and sugar contents of the four origins of Cabernet Sauvignon increased continuously,the titratable acid contents decreased continuously,and the indexes between different harvest period was significant(P<0.05). The change trend of polyphenols content in pericarp was different from that in sugars.The maximum worth date was also different,and the difference between different harvest period was significant(P<0.05). The results of the principal component analysis indicated that the polyphenols in the ripening of Changji Cabernet Sauvignon were better,while the Heshuo Cabernet had more sugary. And the optimal harvest period of Hami Cabernet Sauvignon should be August 31st,the optimal harvest period of Changji Cabernet Sauvignon should be September 19th,the optimal harvest period of Heshuo Cabernet Sauvignon should be September 13th,and the optimal harvest period for Yili Cabernet Sauvignon should be October 5th.