The invention discloses a treatment method of waste liquor obtained after alcohol mother liquor purifying in doxycycline hydrochloride production. The treatment method comprises the following steps: (1) cooling: stirring and cooling the waste liquor to 40-45 DEG C in a regulating reservoir; (2) performing primary flocculation and sedimentation: adding a flocculating agent into cooled wastewater, and adding alkaline to neutralize after performing the flocculation and sedimentation, and mud-water separation; (3) performing secondary flocculation and sedimentation: performing filter-pressing on the liquid neutralized in the step (2) by virtue of a filter press, performing flocculation and sedimentation on filtrate again, and separating mud from water; (4) performing biochemical treatment: performing biochemical reaction on liquid supernatant obtained by mud-water separation through an ozone oxidation decoloration unit, an anaerobic treatment unit and an aerobic biochemical unit; (5) filtering and performing membrane separation: treating the liquid treated in the step (4) through a membrane bioreactor, a nanofiltration membrane and a reverse osmosis membrane. Compared with the prior art, the treatment method has the beneficial effects of high treatment efficiency, stable operation and capacity of eliminating the pollution of wastewater on the environment.