This study was conducted to evaluate the effect of new propylene glycol esters emulsifier on the specific gravity, viscosity, rheology, microstructure of batter and baking characteristics of low-fat cake. The results showed that propylene glycol esters increased the surface tension of oil and promoted changes in fat structure to the α crystalline form as observed by XRD. The small bubbles were protected by propylene glycol esters from defoaming caused by oil. The number of bubbles increased by 1.87 times. Propylene glycol ester significantly increased the specific volume and decreased hardness of low-fat cake.