The invention discloses a water draining control method and device of a dehumidifier. The method comprises the following steps: determining control information that represents the current actual water draining capacity of the dehumidifier; and controlling the water draining operation of the dehumidifier according to the determined control information. Through the method and the device, the problem that water draining control becomes abnormal as the dehumidifier is used for a long time in the prior art is solved, the start and stop of a water pump can be controlled more accurately, frequent start of the water pump is avoided, the comfort is improved, and the service life of the water pump is further prolonged.