Abstract: To obtain the highest yield of barley without influencing the best transplanting season of preceding crop tobacco, the major determinant factors of yield at different sowing dates were determined, the barley variety‘Baodamai 8’mainly promoted by Yunnan Province was used as test material and 6 sowing dates were set to observe the growth process and yield. Through the correlation analysis, path analysis and grey correlation analysis, the relationship between the main agronomic characters and yield of barley after tobacco at different sowing dates was studied. The results showed that: (1) with the delay of sowing date, the growth process was delayed; the days from sowing to seedling emergence was increased along with the delaying of sowing date;(2) the best sowing date of barley after tobacco was September 30 to October 10; (3) the results of correlation analysis, path analysis and grey correlation analysis showed that the effective panicle and thousand-grain weight were the main factors affecting the yield of barley.