The invention discloses a control method of an air conditioner. The control method of the air conditioner comprises: after the air conditioner enters the anti-overcooling mode, acquiring the indoor environment temperature; to a temperature down-regulation operation; when the temperature down-regulation operation is detected, the temperature down threshold is lowered and the air conditioner is controlled to perform a temperature recovery operation. The invention also discloses a control device of the air conditioner, the air conditioner and a storage medium. In the present invention, after the air conditioner enters the overcooling prevention mode, when the indoor ambient temperature is lower than the cooling threshold, whether the air conditioner has a temperature-down operation is obtained, and when the temperature down-regulation operation is detected, the temperature-down threshold of rapid cooling is lowered, and the air conditioner is controlled. The temperature recovery is convenient to obtain the user's comfortable cooling threshold, and avoids the user from manually setting the cooling threshold, thereby improving the comfort of the air outlet of the air conditioner and the user experience.