The results of plasma treatment of soybean seed showed that root quantity during seedling stage was improved,and the flowering rate and bear pods rate were also increased.The yield of all other treatments increased 6.0 kg/hm²-237.0 kg/hm² than that of treatment 7,which was increased 0.2%-7.9%.The economic output increased up to 19.2-873.9 yuan/hm².The yield and economic increment of treatment 2 were the highest,so treatment 2 was the optimal dosage.This provided theoretical basis for the widely use of this technology.