A control method for a laundry treating apparatus comprises a washing machine power supply step of supplying a power to a washing machine interface provided to receive a control command; a course execution step of executing a washing course by the washing machine if the washing course is input to the washing machine interface; a dryer power supply step of supplying the power to the dryer if a preheating request signal is input through the washing machine interface; and a preheating step of including a supply stroke of supplying the air to the drying drum and a heating stroke of heating the air supplied to the drying drum.