Abstract: With the increasing cost of chemical fertilizers and their negative impacts on environment, the research on biofertilizer which could improve soil fertility and promote plant growth has attracted wide attention. In this study, the Bacillus amyloliquefaciens A3 was continually cultured in shaked-flasks containing wastewater from sweet potato starch production and the B. amyloliquefaciens A3 was used as an effective biofertilizer to cultivate vegetable. The objectives of this greenhouse randomized pot experiment were to determine the effect of chemical fertilizers (CN), biofertilizer (BF), bacteria inactivation culture solution (BI), the starch water (SW) and the combination of biofertilizer and chemical fertilizer (BC) on the yield and NO₃- and NO₂- content of the vegetable; NH4+, NO₃-, total dissolved nitrogen (TDN), dissolved organic carbon (DOC) of the soil, and N2O emissions during the experimental period. The results showed that CN and BC increased the yield 5 times higher than CK and there was no significant difference between BC and CN on the effect of increasing the vegetable yield. The effect of BF treatment on the yield of vegetable was not obvious, while the effect of the biofertilizer added with half application rate of chemical nitrogen fertilizer (BCL) on plant yield was similar to that of CN , the NO₃- content of vegetables and soil was 16.4%- 73.6% and 22%- 29% , respectively, lower than that of vegetables treated with CN. BC treatment also reduced the risk of N leaching from the soil and the average N2O discharge fluxes (FLUX₃₀) were 58.3%-73.1% lower than those of the CN. The B. amyloliquefaciens was found to be a feasible low-cost biofertilizer for sustainable vegetable farming and showed the potential for starch wastewater utilization.