The invention provides a washing and drying integrated machine and a drying control method thereof. The washing and drying integrated machine comprises a barrel and a drying air duct communicated with the barrel from an air outlet of the barrel to an air inlet of the barrel. The drying air duct comprises a condenser, a drying fan and a heater which are sequentially arranged. The condenser is connected with a water inlet pipeline. The washing and drying integrated machine comprises a water flow detection and alarming device which comprises a detection module used for detecting the water flow of the water inlet pipeline and an alarming module used for alarming. The detection module is located on the water inlet pipeline. When the detection module detects that the water flow of the water inlet pipeline is smaller than a set value, the alarming module is controlled to sound an alarm. By means of the integrated machine, when no water enters the condenser or the water inflow amount is small and accordingly the condenser does not work, alarm information is sent out to remind a user to dispose the situation in time, energy resources can be saved, and safety is improved.