A suction catheter is generally made of polyvinyl chloride resin which is a hydrophobic material, and when the suction catheter is used, large frictional resistance can be generated, so that the damage to blood vessels and canal tissue is easily caused, and other inflammations are caused. Because of the characteristics of the material, it is inevitable that the suction catheter made of the polyvinyl chloride material has defects. The invention provides an implementation method of a suction catheter with a hydrophilic coating. The method comprises the steps of loading, cleaning, drying, base coating, superficial coating, curing and the like, wherein the concentration of a hydrophilic coating solution is not higher than 5%.