More and more consumers are concerned about the high sodium content in processed cheese. The sodium in processed cheese mainly comes from raw cheese and emulsified salt. The main function of emulsified salt is to promote the uniform distribution of fat in the system and form a uniform network system of protein and fat. In this study， thermal-denatured whey protein was used to pre-emulsified butter to form a whey protein-butter emulsion gel (WPI-EG)， which was then used in cheese processing. The free oil released extent， meltability， texture and microstructure of sodium reducing processed cheese were detected to evaluate the effect of the pre-emulsification process on the quality of sodium reducing processed cheese. The results showed that the formation of WPI-EG in the pre-emulsification process could effectively promote the uniform fat distribution in the processed cheese， and form the uniform structure and texture. The pre-emulsification process improved the hardness， stickiness and chewiness of the processed cheese， and led to lower oil extraction of the cheese. Compared with the non-pre-emulsified cheese (NEC)， the pre-emulsified processed cheese (30%EC) with 30% less sodium emulsified salt decreased the sodium content by 52.9 mg/100 g， the hardness increased by 27.1%， the oil extraction property decreased by 0.53 cm. The microstructure showed that the fat distribution and protein network structure of 30%EC were more uniform and dense. This study showed that the pre-emulsification process could effectively reduce the amount of sodium containing emulsified salt in the processed cheese and improve the quality of the cheese.