The invention discloses a clothes dryer/washing-drying all-in-one machine control method and a clothes dryer/washing-drying all-in-one machine and relates to the technical field of clothes dryers. The clothes dryer/washing-drying all-in-one machine is designed for solving the problem that condensed water of an existing heat pump type clothes dryer/washing-drying all-in-one machine cannot be completely discharged out. The clothes dryer/washing-drying all-in-one machine control method comprises the steps that the condensed water produced by a heat absorber is collected by a condensed water collecting device, the water level of the collected condensed water is detected, an air supply fan is controlled to reduce rotating speed after the water level of the condensed water reaches or exceeds a first preset water level, and a draining pump is started to discharge out the condensed water after speed reduction is completed; after water discharge is completed, the rotating speed of the air supply fan is restored to original rotating speed. In addition, the clothes dryer/washing-drying all-in-one machine adopts the control method, the rotating speed of the air supply fan is reduced when the draining pump discharges water so that the liquid level in the condensed water collecting device can be kept horizontal basically, the detection accuracy of the water level is improved, and it is ensured that condensed water can be completely discharged out.