In order to study the effects of Fenlong tillage on photosynthetic physiological characteristics and yield of sweet sorghum， 4 tillage methods， including conventional tillage （CK）?， Fenlong tillage to 30 （FL30） and 50 （FL50） cm depth， deep tilling to 40 cm depth （DT40）， were set up in Helan Mountain farm， Yinchuan City， Ningxia Province， with ‘BJ0603’ as material. Agronomic traits， yield and photosynthetic physiological characteristics of sweet sorghum were measured and analyzed. The results showed that， compared with CK and DT40 treatments， the number of stem nodes， dry matter content， sugar content and grain yield of sweet sorghum significantly increased by Fenlong tillage （FL30 and FL50）. The correlation analysis showed that the biological yield and grain yield were positively correlated with plant height， stem node number， dry matter content and sugar content. The photosynthetic physiological indexes of sweet sorghum cultivated with Fenlong tillage （FL30， FL50） were better than CK treatment during the whole growth stage， and better than DT40 treatment at flowering and maturity stages. Principal component analysis showed that the comprehensive values of FL50， FL30， DT40 and CK treatments were 0.20， 0.11， -0.03 and -0.14， respectively， which indicated Fenlong tillage was helpful to improve the photosynthetic physiological characteristics of sweet sorghum.