The invention relates to a loop control method for the biochemical sewage treatment process, which comprises the following steps of: performing cascade control on the organic load of inflowing water, and controlling 'labor force' of the biochemical sewage treatment, namely the number of 'foods' of microbes so as to reduce the energy consumption in a sewage lift link; performing cascade control on dissolved oxygen concentration in an aeration tank to realize air supply of the aeration tank according to the need so as to reduce the energy consumption in a fan aeration link; and performing feedforward-cascade control on the sludge concentration in the aeration tank, and controlling the number of microbes in a sewage treatment system so as to reduce the energy consumption in a sludge return link. The loop control method effectively controls the biochemical sewage treatment process with three main energy consumption links, namely sewage lift, fan aeration and sludge return, obviously reduces the energy consumption in the biochemical sewage treatment process on the premise of guaranteeing that effluent steadily meets the standard, and solves the problem that the traditional PID single loop control is difficult to achieve ideal control effect by implementing loop control cascade control and a human intelligent control algorithm,.
