Sodium caseinate, as a good emulsifier and emulsifying stabilizer, plays an important role in the quality of milk beverage. Sucrose as the sweetener, can improve the taste of milk beverage. But the structure and property of casein can easily be influenced by the micro environment. To analyze the effect of sucrose on the structure and emulsification of sodium caseinate, changes of fluorescence spectra and surface hydrophobicity of sodium caseinate were investigated by fluorescence spectrum. Changes of sodium caseinate emulsion droplet hydrodynamic diameters were determined by dynamic laser scattering. Backscattering profiles and stability index (TSI) were evaluated by turbiscan spectroscopy stability analysis. The results showed that the interaction between sucrose and sodium caseinate resulted in the endogenous fluorescence quenching of sodium caseinate (KS＜2.0×1010 L·mol-1·s-1), which belongs to a dynamic quenching mechanism. The strength between sucrose and sodium caseinate was hydrogen bonding and hydrophobic interaction. Surface hydrophobicity of sodium caseinate significantly was enhanced (p<0.05), leading to the increasing in the degree of sodium caseinate aggregation and the formation of the soluble aggregates. With increasing of sucrose concentration, the emulsion droplet size stabled by sodium caseinate increased, resulting from protein aggregates preferred to adsorb on the oil-water interface under high pressure homogeneous. The backscattering profiles of sodium caseinate emulsions showed that the emulsions stability increased with the increasing of sucrose concentration. The instability phenomenon (such as stratification, concentration change, and emulsion droplet transfer) is more difficult to happen. Stability index significantly increased (p<0.05) also with the increasing of sucrose concentration. The emulsion stability increased by sucrose.