The invention mainly relates to a new method for preparing porous hydrogel by adopting the low temperature photopolymerization. In the method, the temperature of the low temperature environment is 0-150 DEG C; the hydrogel uses one or two of epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate and acrylic resin as a main body; and one or water, ethanol, acetone, methanol, acetonitrile, dioxane, chloroform, ethyl acetate, butyl acetate, tetrahydrofuran, propanol, butanol, dichloromethane, toluene, diethyl ether, propyl ether, heptane, cyclopentane, cyclohexane and petroleum ether is used as solvent; the weight proportion of acrylic resin is 10%-500%; and the initiator adopts common photoinitiator BP, 651, 907, ITX, 1173, 184, 2959, 369, TPO, 819, CQ or 784 and is 0.1wt%-5wt% of acrylic resin.