The invention provides a polymeric hydrogel for dressing and a preparation method of the polymeric hydrogel, belonging to the fields of radiation chemical and biomedical polymeric materials. The polymeric hydrogel is prepared from gelatin, sodium carboxymethylcellulose, gulcomannan, water-soluble chitosan, polyglutamic acid, hyaluronic acid and the like which are good in biocompatibility through blending, hot orientation and packaging; by controlling the temperature of hot orientation as well as orientation force and orientation time, the mechanical strength of the hydrogel is enhanced, and through high energy ray irradiation crosslinking, a regular aggregation structure obtained from the orientation is further immobilized and enhanced so as to synthesize high-strength dressing. The hydrogel disclosed by the invention is good in physicochemical and biological properties, high in tensile strength and good in transparency, and the hydrogel is relatively good in antibacterial and healing-promoting effects when applied to dressing. The polymeric hydrogel for dressing disclosed by the invention not requires an adhesive, a non-woven fabric or other reinforcing layers during preparing, and the polymeric hydrogel is simple in process and low in energy consumption; and the polymeric hydrogel can achieve sterilization and disinfection when radiating, and the polymeric hydrogel can reduce production cost and bring about benefit for production in a large scale.