The invention relates to an antifogging agent and especially relates to an automobile glass antifogging agent. The automobile glass antifogging agent comprises, by weight, 16-20% of sorbitan monstearate (S-60), 2-5% of methyltrifluoropropyl silicone oil, 14-18% of sorbitan monopalmitate (S-40), 2-5% of volatile perfluoro-oil, 2-5% of 1, 5-pentanediol, 0.5-2.5% of sodium benzoate, and 45-65% of deionized water. The automobile glass antifogging agent has excellent hydrophobicity and antifogging function, can prevent a high temperature, can improve dirt resistance, can prolong antifogging time, can improve antifogging effects, and has a wide use range, a low cost and no side effects on the human body. Through coating automobile outer glass and rearview mirrors, the automobile glass antifogging agent has effects of preventing rain, cleaning glass and protecting a wiper. The automobile glass antifogging agent can be dissolved in water, has no easy combustion and blast risk and is portable.