Inner-partition ventilation anti-blocking water drainage pipe fitting

The utility model relates to a building water drainage system pipeline connecting piece, in particular to an inner-partition ventilation anti-blocking water drainage pipe fitting. The inner-partition ventilation anti-blocking water drainage pipe fitting comprises a pipeline fitting main body and three bell mouths, wherein the outer diameter of the pipeline fitting main body is larger than those of the three bell mouths; one end of the first bell mouth is connected with one end of the pipeline fitting main body through a first connecting body; the second bell mouth is connected with the other end of the pipeline fitting main body through a second connecting body; the third bell mouth is arranged in middle of the pipeline fitting main body and communicated with the pipeline fitting main body; an inner partition is arranged in the pipeline fitting main body; the inner-partition ventilation anti-blocking water drainage pipe fitting further comprises a sewage discharge opening and a sealing cover; one end of the sewage discharge opening is connected with the middle of the pipeline fitting main body through a circular arc; an external thread is formed in the other end of the sewage discharge opening; an internal thread matched with the external thread is formed in the sealing cover; the sealing cover is in threaded connection with the other end of the sewage discharge opening; a first water flow channel formed by the first bell mouth, one side of the inner partition and the second bell mouth is shaped like Chinese character yi; a second water flow channel formed by the third bell mouth, the other side of the inner partition and the second bell mouth takes the shape of L rotating by 90 degrees clockwise.