The invention discloses a control method and apparatus for a humidifying lamp tube, and a humidifier. The control method for the humidifying lamp tube comprises the steps of obtaining a detection humidity value of a humidified space; calculating a humidity difference value between a preset target humidity value and the detection humidity value; judging whether the humidity difference value is greater than or equal to a preset difference value threshold value or not; and if the humidity difference value is greater than or equal to the preset first difference value threshold value, starting lamp tubes of corresponding quantity according to the humidity difference value and humidity rate of change. According to the scheme, by comparing the humidity difference value with the preset difference value threshold value, the lamp tubes of corresponding quantity are started to realize multi-stage control of humidifying amount, and all lamp tubes are not required to be turned on and turned off at the same time, so that the humidifying function is relatively accurate; and in addition, electric energy can be reduced and the service life of the lamp tubes can be prolonged.