The pit sewage pump is an important conveying equipment of pit sewage treatment system,once the failure,it will affect the normal operation of the whole sewage system.To a plant even retreat unit coating section pit sewage pump,for example,in less than 1 month of operation on the machine,alarm again,unable to complete the work required,after dismantling the machine after the inspection,found that the pump internal bearing lubrication is poor,impeller and pump cover serious wear and tear.For the sewage pump in the inspection and maintenance of the various problems found in the analysis of the causes of various types of failure,and ultimately diagnosed as a long time idling pump,and put forward the pit sewage pump improvement methods to extend the service life.