Liquid cheese stored at room temperature, which can remain stable at room temperature for 3~6 months, is a kind of processed cheese. After high-temperature treatment, the number of microorganisms in the liquid cheese system reaches the commercial aseptic level because the liquid cheese is an unstable emulsion system with oil in water. During the storage at room temperature, due to the migration of dispersed phase particles and the change of particle size, the emulsion system is prone to instability, such as aggregation, flocculation, oil slick and precipitation. It affects the product's quality and shortens the product's shelf life. Therefore, it is important to accurately judge the stability of liquid cheese to optimize its processing conditions. However, the stability evaluation of traditional liquid dairy products is mainly through accelerating the visual observation of stratification and precipitation, dynamic light scattering, and the lack of fast, reliable and quantitative evaluation standards. When testing fluid stability, Turbiscan multiple light technologies does not need to pretreatment the sample. It can detect the intensity of backscattered light and transmitted light in real-time, calculate the migration rate of particles inside the system, the thickness of the precipitation layer, and the instability index of the system, so it is an effective method to evaluate the stability of the fluid. The parameters such as the migration rate of particles in the system, the thickness of the precipitation layer and the instability index of the system are calculated, so it is an effective means to evaluate the stability of the fluid. Turbiscan multiple light scattering technique was used to evaluate the effect of emulsified salt, emulsifier, stabilizer and sweetener on the stability of room temperature liquid cheese. At the same time, according to the response value of TSI and sensory score, the optimum formulation conditions of room temperature liquid cheese were optimized by the Box-Behnken experimental design model of response surface method, and the main factors leading to the instability of room temperature liquid cheese were analyzed. It was found that when the amount of emulsified salt was 0.20%, 0.40%, 0.60%, 0.80%, the instability index increased from 0.4 to 12.6 after 24 hours; when the amount of emulsifier was 0.80%, 1.0%, the instability index increased from 0.95 to 3.9 after 24 hours. When the amount of stabilizer was 0.7% and 0.9%, the instability index increased from 0.9 to 1.3 after 24 hours, but the effect of sweetener on the overall stability of the system was insignificant. The influence order of various factors on the instability index and sensory score of room temperature liquid cheese is emulsified salt (A) > emulsifier (B) > stabilizer (C). When emulsified salt was added to 0.60%, emulsifier was 0.60%, stabilizer was 0.70%, and sweetener was 5.5%, the product quality was the best and the stability was the highest. Under the optimized conditions, the overall instability index of the sample at 37 ℃ for 24 hours was 0.80, the variation of backscattered light intensity at the top and bottom of the sample was 0.66 and 0.78 respectively, and the sensory score was 89.The results show that the problem of delamination of room temperature liquid cheese can be well solved, and the stability of room temperature liquid cheese can be improved by adjusting the emulsified salt, emulsifier and stabilizer.