The invention discloses a method for strengthening sludge reduction of an aerobic-sedimentation-anoxic process. In the method, the aeration control of an anoxic pond is increased at the anoxic pond of the conventional OSA process, and aeration parameters such as bubbles, time, gas-liquid ratio, oxidation-reduction potential and the like are controlled, so that the sludge reduction effect of the conventional OSA is improved obviously. For the aeration control of the anoxic pond, aeration equipment of an aerobic biological treatment unit of the conventional process is adopted to perform simple pipeline extension, and the sludge reduction effect of the OSA is improved obviously by controlling the parameters without changing the cost of processing sludge. The aeration control technology can realize automated operation without personnel. The aeration control technology has the advantages of low air consumption, short aeration time, no power consumption, and utilization of air generated by the conventional aeration equipment, and thus the operating cost is close to zero.