A glass optical lens cleaning agent is prepared from, by weight, 60-70 parts of ethylene glycol butyl ether, 45-55 parts of propyl alcohol, 25-35 parts of octyl phenol polyoxyethylene ether, 30-45 parts of alkylolamide, 5-15 parts of potassium carbonate, 40-55 parts of ammonia water, 10-20 parts of triethanolamine and 200-260 parts of water. A preparation method comprises the following steps that 1, water is heated to reach 70-80 DEG C; 2, the ethylene glycol butyl ether, the propyl alcohol, the octyl phenol polyoxyethylene ether, the alkylolamide, the potassium carbonate, the ammonia water and the triethanolamine are sequentially added slowly, stirring is performed while adding to make the raw materials fully react for dissolution; 3, cooling is performed to reach 20-30 DEG C, ageing is performed for 1-2 hours, and the glass optical lens cleaning agent is obtained. The cleaning agent is non-corrosive to a glass optical lens and is environmentally friendly and non-toxic.