To study the influence of sesame protein isolate on cheese system, the characteristics of microstructure and thermal properties of cheese contained sesame protein isolate were investigated. Cheeses made from mixture milk with 0, 4%, 8%, 12% protein substituted by sesame protein isolates in total milk protein were prepared. Adding sesame protein isolate in cow milk resulted fat globular smaller and more regular, showed the emulsifying and homogeneous properties of sesame protein isolate. DSC analysis showed the thermodynamic properties were influenced by sesame protein isolate, one new absorption peak was detected and the peak temperature varied with sesame protein isolate content. The interact mode of sesame protein isolate and casein based on the present results were discussed and the research results were published. 