Improved discharging tube of internal combustion engine

The utility mode relates to an improved outflow tube of a combustion engine. The utility mode is characterized in that the outflow tube is divided into two sections including a tube head and a tube shaft in a bent position between a first outflow port and a second outflow port of a head end of the tube, and the tube head and the tube shaft are in sleeve connection via screw threads and the like. The outflow tube which was not adaptable for compression molding can employ compression molding of high quality casting, thereby overcoming the shortages of the original sand casting and low pressure casting on the whole and improving the quality of products greatly.