Transglutaminase(TG)as a cross-linking agent took place crosslinking reaction with soybean protein isolate(SPI).The effects of thermal treatment temperature,TG dosage,cross-linking temperature and duration,SPI concentration,and cross-linking pH on the solubility and emulsifying properties of SPI were determined by single-factor experiments.The results indicated that after 4% SPI was heated at 70 ℃ for 30 min,and cross-linked with TG of 2 U/g SPI in pH 6.5 and at 45 ℃ for 1 h,the solubility,emulsifying activity and emulsion stability of SPI reached 0.037 g/mL,328.868 cm-1and 0.951 respectively.Compared with the untreated 4% SPI,the emulsifying activity and emulsion stability of SPI cross-linked with TG significantly increased,but the solubility decreased significantly.