To solve the problems in the process of rennet casein,such as without curd or incomplete curd and appearance of white precipitate before the curd,the white precipitate disappearance conditions and optimum process conditions were studied by single factor experiment and orthogonal test using the key technologies of assaying the enzyme activity and promoting curd by adding CaCl2.The results showed that the best conditions for white precipitate disappearance were HCl concentration of 0.3moL/L with additive rate of 45mL/min,CaCl2 concentration of 25% with additive rate of 45 mL/min.The best curd conditions were 2% CaCl2,40℃,pH 6.5,heating rate of 2 ℃/min.Under this condition,the average yield of the product achieved 70.93%,the average protein content was up to 91.78%,the ash content reduced to 5.30% and the sensory quality was good.