The utility model discloses an anaerobic-aerobic treatment system for port oily sewage. The anaerobic-aerobic treatment system comprises an inclined plate oil separation tank, a stirring reaction tank, a first sedimentation tank, an anaerobic tank, an aerobic tank and a second sedimentation tank which are sequentially connected and communicated with one another, the medicine dispensing box is communicated into the stirring reaction tank through a liquid conveying pipe; the sludge collecting hopper is connected with a sludge discharge pipe of the first sedimentation tank through a pipeline; thefirst oil sludge tank and the second oil sludge tank are respectively arranged below the inclined plate oil separation tank and the sludge collection hopper and are respectively communicated with sludge discharge pipes of the inclined plate oil separation tank and the sludge collection hopper; the aeration pump is communicated to a microporous aeration disc arranged at the bottom of the aerobic tank through an air delivery pipe, and a valve is arranged on the air delivery pipe; according to the anaerobic-aerobic treatment system for the port oily sewage, the treatment system meeting the requirements for removing complex types of sewage and being high in treatment difficulty is provided, the treatment system can adapt to the port oily sewage with large water quantity and water quality fluctuation, and treatment energy consumption is low; in addition, the treatment system is simple to operate and easy to maintain.