The invention discloses an assembly unit for a compressor crankshaft and muffler head assembly machine, comprising an assembly mounting support mounted on a ground; an assembly plate is mounted on the assembly mounting support, the upper plane of the assembly plate is fitted with an assembly electric slide through pads, a slider of the assembly electric slide is fitted with two parallel clamp plates through a slider connecting plate, a workpiece holder is provided between the two parallel clamp plates, the lower plane of the workpiece holder is attached to the upper plane of the assembly plate, a workpiece is placed in the workpiece holder, the side of the workpiece holder is fitted with a fixing block connecting plate, both ends of the fixing block connecting plate are fitted with connecting plate fixing blocks, the lower planes of the two connecting plate fixing blocks are each fitted with a roller mounting seat, and both the lower planes of the two roller mounting seats are attached to the upper plane of the assembly plate. In this way, the assembly unit is implemented.