Abstract: Abstract: 【OBJECTIVE】The aim of this article was to study growth characteristics and above ground dry matter accumulation of sweet sorghum (Sorghum bicolor L.) under diffferent planting density and nitrogen application amount levels, and provide a theoretical basis for high yield cultivation of sweet sorghum in seashore saline soil. 【METHOD】Using the method of two factors randomized block experiment to investigate the effects of planting density and nitrogen application amount on growth characteristics, dry matter accumulation and the interrelationship among biomass yield, sugar brix of ST008 plant grown in seashore saline soil were analyzed by correlation analysis and path analysis. 【RESULTS】The suitable planting density and nitrogen application amount for ST008 was 12000 plant/hm2 and 300 kg/hm2, respectively. Under this condition, the plant height, leaf number and stem diameter of sweet sorghum were maintained within reasonable ranges, and higher biomass yield and sugar brix was achieved. The dry weight of above ground plant from jointing to heading stage and stem yield and sugar content were positively correlated respectively, which had highest direct path coefficient contributed to the stem yield and sugar content. 【CONCLUSION】The biomass yield of sweet sorghum wa highest when planting density and nitrogen application amount for ST008 was 12000 plant/hm2 and 300 kg/hm2, respectively . The key point of increasing sweet sorghum yield and sugar content was to enhance the photosynthetic production after the jointing stage..