This paper studied the fermentation rules of apple cider vinegar from fruit juice, to provide a theoretical guidance for the production of apple cider vinegar. Using Fuji apples as raw materials, the process parameters (fermentation temperature, fermentation time, stirring speed, and inoculation amount) of apple cider vinegar fermentation were optimized through single-factor experiments and response surface analysis. The results indicated that the fermentation temperature had no significant effect on the total acid content of apple cider vinegar fermentation, the fermentation time had an extremely significant effect on the total acid content of apple cider vinegar fermentation, and the stirring speed and inoculation amount had a significant effect on the total acid content of apple cider vinegar fermentation. Through process optimization, the optimal process parameters for apple cider vinegar fermentation are fermentation temperature of 33 °C, fermentation time of 39 h, stirring speed of 1 500 r/min, and acetic acid bacteria inoculation amount of 7%. Under such conditions, the total acid content of fermented apple cider vinegar is 62.22 g/L, very close to the predicted value of the model, indicating that the process parameters of acetic acid fermentation obtained by response surface methodology (RSM) optimization are reliable and can be used for actual production prediction.