The invention discloses an automatic abrasive machining device for the end face of a pipe fitting. The automatic abrasive machining device comprises a mounting base and an annular base, wherein the mounting base is fixed to the pipe fitting; the annular base is fixedly connected with the mounting base; the automatic abrasive machining device is characterized in that one side of the annular base isfixedly connected with a pressing plate; an annular chain is arranged between the annular base and the pressing plate; an inner wheel groove, an inner clamping groove, an outer wheel groove and an outer clamping groove are formed inside the annular base; an inner idler wheel is arranged inside the inner wheel groove; the inner idler wheel is connected with an inner slider arranged inside the inner clamping groove through a central spindle; an outer idler wheel is arranged inside the outer wheel groove; the outer idler wheel is connected with an outer slider which is arranged inside the outerclamping groove through the central spindle; the inner slider and the outer slider are both connected to a movable sliding base; the movable sliding base is fixedly provided with an abrasive machine and a speed reducing motor; a spindle of the abrasive machine is connected with a grinding wheel matched with the end face of the pipe fitting; and an output shaft of the speed reducing motor is connected with a chain wheel which is matched with a chain. The automatic abrasive machining device disclosed by the invention has the advantages of wide application range, low labor intensity, high machining efficiency and low energy consumption, and can greatly lower the machining cost.