Sweat sorghum has stooling and sweat sorghum was detillered ordinarily in cultivation. Lodging was an important limiting factor of sweet sorghum production and extension. The effects of detiller on lodging were determined by surveying agronomic traits related lodging of 3 sweet sorghum varieties in normal or detilling. The results showed that stool ratio was 28.8%-52.0% in normal. Lodging ratio, the number of total plants, plant height, gravity center height, knob length and lodging coefficient decreased, and stalk diameter, break-off force and main stem fresh weight increased in detiller. Difference of plant height, main stem fresh weight and lodging coefficient of 5-7 knob were small, and difference of other traits were significant at 0.05 or 0.01 level. Correlation between lodging ratio and plant height, stalk diameter, gravity center height, main stem fresh weight and length of 1-4 knob were significant at 0.01 level, and correlation between lodging ratio and lodging coefficient of 5-7 knob was significant at 0.05 level. The number of total plants, competition among plants plant height and gravity center height were decreased, break-off force was increased, stalk diameter and main stem fresh weight were significantly increased, knob length was shortened by detilling. As a result, lodging resistance was significantly improved and lodging ratio was significantly decreased.