In this paper, the effect of glutamine transaminase (TGase) on the crosslinking of soybean protein isolate (SPI) was studied. Taking gel strength as an index, response surface methodology (RSM) was used to investigate the effects of TGase content, enzyme reaction time and enzyme temperature on SPI gel properties, and the optimal process parameters were obtained through optimization. Experimental results show that the addition of enzyme and temperature have significant effects on the gel strength of soy protein isolate (p< 0.05).The best process of protein gel performance was obtained, with the enzyme content of 3.63%, the enzyme reaction temperature of 38.15℃, and the enzyme reaction time of 2.04 h. At this time, the gel strength of protein gel reached the extreme value of 3018. Studies have shown that TGase can promote soy protein isolate to form a good gel.