A method for producing ethanol from steam-exploded sweet potato by fermentation includes subjecting sweet potato to a steam explosion treatment, subjecting the sweet potato after the steam explosion to saccharification and fermentation, and collecting ethanol produced by the fermentation. The sweet potato can optionally be subjected to a pre-treatment utilizing a short-time, low-pressure steam explosion technology, which omits the long-time cooking process for the starch-based raw material and reduces the energy consumption for producing ethanol by fermentation. The method permits the steam explosion-treated sweet potato t be subjected directly to saccharification and solid-state fermentation, the water content in fermentation mash is reduced greatly so as to increase the concentration of ethanol in fermentation mash, reduce the energy consumption for distillation, reduce the subsequent treatment steps for the waste water and lower the producing cost, which are all beneficial to the comprehensive utilization of sweet potato.