The objective of this study was to estimate the effects of soluble hydrolysate and soluble / insoluble aggregates of soy protein isolate( SPI) on the quality of emulsified sausage. The elastic modulus of meat emulsion,the textural property,cooking yield and microstructure of emulsified sausage were estimated. The microstructure was observed by environmental scanning electron microscopy( ESEM). The results showed that all kinds of SPI significantly( P < 0. 05) improved the cooking yield of sausage. Incorporation with insoluble aggregate of SPI remarkably enhanced the elastic modulus and texture,and exhibited a more continuous,compact and less porous structure. The soluble aggregate of SPI had no obvious effect on the rheological and textural properties,but induced an exquisite network structure. However,the soluble hydrolysate of SPI badly destroyed the texture of sausage,and presented a fractional,discontinuous and non-cross linked structure. Native SPI reduced the elastic modulus,but had no significant effect on texture of sausage. The results of this study would guide further study of SPI application in meat products.