Milk protein and soy protein isolate with different compositions and structure were used to prepare ice cream emulsions. The effect of sucrose concentration on the destabilization of fat globules at low temperatures in these two protein-stabilized emulsion systems was studied. Parameters such as Fourier transform infrared spectroscopy (FTIR) measurement of protein/sucrose ester complex, protein surface coverage, zeta potential, particle size and microstructure of whipped-frozen emulsion were analyzed. Furthermore, with the optimal concentration of sucrose ester, the effect of protein compositions on the destabilization of fat globules and ice cream properties were studied by partially substituting milk protein with different ratios of soy protein isolate. The results indicated that the interaction between sucrose ester and milk protein or soy protein isolate on the fat globule surface involved complexation and competitive adsorption. When the sucrose ester concentration was increased from 0 to 0.3%, the interaction between protein and sucrose ester on the surface of fat globule was mainly dominated by competitive adsorption. At this sucrose ester concentration, the surface protein coverage in the two protein-stabilized ice cream emulsion systems was significantly reduced. The partial coalescence degree of fat globules was relatively high. The ratio of milk protein to soy protein isolate was adjusted while sucrose ester mass fraction was kept at 0.3%. Ice cream showed higher overrun values and the best melting resistance ability when the ratio of milk protein to soy protein isolates was at 7∶3, which was more favored to the occurrence of partial coalescence.