Processing method of high density composite pipe

The invention relates to a high density composite pipe which is prepared by the following raw materials in parts by weight: 100 parts of high density polyethylene, 5-15 parts of nano calcium carbonate, 5-15 parts of filler, 1-5 parts of a lubricant and 1-5 parts of a solubilizer. The processing method comprises the following steps: putting the raw materials in parts by weight in a high speed mixer to primary mix for 3-5 minutes; uniformly mixing and stirring; extruding particles by the primarily mixed material in a twin-screw extruder, and controlling the temperature at 200-220 DEG C; putting the dried mixed material in a pipe extruder and extruding to obtain a high density polyethylene compound pipe; and cooling: cooling by water at 70-80 DEG C and setting. The processing method provided by the invention is convenient to operate, the strength of the high density polyethylene compound pipe is improved by applying assistants such as a bulking agent, and the comprehensive performances such as tensile strength can be remarkably improved. The raw materials are stirred at low speed and are prevented from being heated to lead to deterioration, so that the cost is saved to a certain degree.