Disclosed are an anti-freezing agent for protecting a biological tissue from being damaged during a freezing treatment and a preparation method therefor. The method for preparing the anti-freezing agent involves mixing ethylene glycol, water and dimethylsulfoxide homogeneously to form a matrix, and then slowly adding sodium polyacrylate. The prepared anti-freezing agent is coated onto biological tissue during a freezing treatment such that damage to the biological tissue is reduced.