A sewage by-pass drainage system for sewage pipe works comprises a submerge pump provided in a first manhole, a sewage pipe between a second manhole and a third manhole located at a downstream side of the first manhole being taken as a working zone, an upstream side stop plug being provided at an outflow side of a sewage pipe between the first manhole and the second manhole, and a downstream side stop plug being provided at an inflow side of a sewage pipe opening to the third manhole, a suction pipe of a suction drainage apparatus provided on the ground being projected into an upstream side of the upstream side stop plug, a discharge pipe of the suction drainage apparatus being projected into a downstream side of the downstream side stop plug, and a discharge pipe of the submerge pump being arranged to the downstream side of the downstream side stop plug. By this, a sewage or the like can be drained even from the deeply buried sewage pipe so that an odor may not leak above the ground.