The invention discloses an environmentally-friendly treatment method for gutter oil, and the environmentally-friendly treatment method comprises the following steps: a) pretreatment of gutter oil, tobe more specific, putting the collected gutter oil on a the filter screen, spraying a collected filtered matter with hot water, heating the collected filtered matter in a heating container, and layering the collected filtered matter after standing to obtain a turbid liquid, upper oil and underlying oil; b) treatment of an auxiliary material, to be more specific, taking straw powder and plant ash according to a weight ratio of 10-20:1 to prepare the auxiliary material; c) treatment of the turbid liquid and the underlying oil, to be more specific, taking the auxiliary material, the turbid liquidand the underlying oil into a fermentation tank, then adding methane bacteria to ferment; and d) continued fermentation, to be more specific, after the end of the fermentation, discharging the liquidin the fermentation tank, dividing the excess turbid liquid into 2-5 parts, adding 1 part of the turbid liquid, the methane bacteria and the auxiliary material to the fermentation tank for post-fermentation, after the end of the post-fermentation, discharging the liquid in the fermentation tank, and repeating the above steps. The method is environmentally friendly in treatment process, enhancesthe utilization rate of the gutter oil, and has simple operation and complete fermentation process.