Abstract: In order to enrich tomato varieties and obtain fermented tomato sauce with better taste and quality,tomato was used as raw material. On the basis of single factor experiment,color difference,total acid and organic acid content were used as the test indexes. Using total acid content as response value,the fermentation conditions of tomato were optimized by response surface method. The results showed that when the ratio of Lactobacillus botanica,Lactobacillus acidophilus and Bacillus coagulans was 1:2:1,the acid production of tomato sauce was the highest,and the optimum fermentation conditions were as follows:Fermentation temperature was 28 ℃,fermentation time was 30 d,the inoculum size was 1.8% and the content of V_C-Na was 0.5%. The total acid content of fermented tomato sauce was 25.16 g/kg,the organic acid content was higher than that of natural fermentation. The finished product was fresh in color,rich in aroma and mellow aftertaste.