The invention relates to a potato type ethanol wastewater treatment method and system. The method comprises the following steps: carrying out high-temperature anaerobic reaction on the effluent which is obtained by desanding and homogenizing high-concentration sewage, introducing biogas residue into a sludge system via rotating grill, carrying out air flotation and thin film filtration on the effluent to reduce the concentration of the suspended substances in the effluent to 50-100mg/L, and separately returning the sludge to a sand basin I and a sludge removing system; removing PO4<3->, NH4<+> and Mg<2+> in the effluent obtained after the thin film filtration via a struvite reaction tank, and discharging the struvite precipitate; homogenizing the effluent with the medium-temperature anaerobic temperature of 33-37 DEG C and the COD (chemical oxygen demand) about 3000mg/L and the low-concentration sewage after desanding, and then entering an aerobic biochemical and aerobic MBR (membrane biological reactor) so as to enable the concentration of the sludge to be 10-15mg/L, the dissolved oxygen to be 4-6mg/L and the COD in the effluent of the aerobic MBR to be 100-150mg/L; and carrying out O3 oxidization and biological active carbon reaction on the effluent of the aerobic MBR, wherein the adding amount of O3 is 20-50mg/L, the dissolved oxygen is 1-3mg/L, and the COD is 50-60mg/L.