Abstract: The copolymer of DADMAC and NIPAAm is synthesized by radiation copolymerization. The experimental results show that transparent, highelastic and highabsorptive copolymer are obtained in the conditions of fit ratio of two monomer; crosslinker content and absorbed dose. The strength of copolymer is reinforced by the means of increasing NIPAAm content and absorbed dose, and it will get to constant. It is revealed that the dose rate doesn't have any obvious effect on this property. Although the equilibrium swelling ratio of copolymer is a bit reduced as the mechanical strength of that is reinforced, it is still a good absorbent. In addition, the results also show that the temperature sensitivities of the copolymer are disappeared in copolymer even with low content of DADMAC.