Pipe fitting joint, filter and air conditioner

The utility model relates to the technical field of pipeline connection, and provides a pipe fitting joint, a filter and an air conditioner, the pipe fitting joint comprises a straight pipe section with two through ends, a first annular recess is formed on the pipe wall of the straight pipe section, and a first annular bulge is formed on the first annular recess on the inner wall of the straight pipe section; an annular supporting face is formed on the side, facing the end of the straight pipe section, of the first annular protrusion, and the central axis of the annular supporting face and the pipe axis central line of the straight pipe section are located on the same straight line. When the sub-pipe is inserted into the straight pipe section, the end face of the sub-pipe abuts against the annular supporting face, the situation that the sub-pipe and the straight pipe section are relatively inclined can be avoided, and the welding quality and butt joint precision of the sub-pipe and the pipe fitting connector