The effect of different sowing dates on the starch accumulation and grain yield in sorghum hybrid"Chiza 28"was studied. The results showed that content of total starch,amylopectin,amylose and the ratio of amylopectin to amylose increased continuously along with the advance of grain filling process,reached the maximum at maturity stage. Total starch content and amylopectin content in sowing date Ⅲ were the highest,at 75.5% and 66.91%,respectively. Amylose content in sowing date Ⅴ was 8.67%,which is the highest. Ratio of amylopectin to amylose content in sowing date Ⅱ was the highest at 8.19. Timely sowing（mid-May in Chifeng）promoted the increase of total starch and amylopectin contents,which improves sorghum grain quality. Feasible late sowing promoted the increase of amylose content. Timely sowing promoted the increase of yield of sorghum grain.