In order to reduce the costs of production and increase the lactic acid yields, this research adopts Bacillus subtilis to substitute enzymes. The method used in the study is two-phase fermentation - inoculate Bacillus subtilis to food waste to produce sugar, and then inoculate Lactobacillus to food waste to yield lactic acid. 87.22 g l–1 of total sugar can be obtained from non-autoclaved food waste in 30 h of saccharification at 40 centigrade. After two-phase fermentation, the optimal lactic acid concentration was 50.77g/L. The results indicate that two-phase fermentation is better than synchronous saccharification fermentation.