The embodiment of the invention provides a method and device for judging refrigerant leakage of an air conditioner, and relates to the technical field of air conditioners. By adoption of the method and device for judging refrigerant leakage of the air conditioner, the purpose of detecting refrigerant leakage of the air conditioner is achieved. The method for judging refrigerant leakage of the air conditioner specifically comprises the steps that the current outdoor environment temperature, the current outdoor liquid pipe temperature, the current indoor return air temperature and the current indoor anti-freezing temperature of the air conditioner are obtained, and whether refrigerants in the air conditioner leak or not is judged according to the difference value between the absolute difference value of the current outdoor environment temperature and the current outdoor liquid pipe temperature and a first preset threshold value, and the difference value between the absolute difference value of the current indoor return air temperature and the current indoor anti-freezing temperature and a second preset threshold value.