Soy protein isolate(SPI) were preheated at 80℃ for 10 hours with sodium chloride as a coagulant.protein was denatured at 95℃ for 30 minutes.The different concentration,ionic strength and pH conditions of denatured protein were studied.The soybean protein texture and gel properties were analyzed.The results showed that the solubility of the protein with pH7.0 and preheated at 80℃ for 10 hours was less than untreated SPI.;the protein gel formation with pH2 and preheated at 80℃ for 10 hours is much better than untreated SPI;in a certain range,with the increase of protein concentration and ionic strength,the gel formation is getting better.