The present disclosure relates to a method of controlling a garment folding machine, which may effectively prevent damage to a drive motor and a loss of power caused by an overload of the drive motor by accurately detecting and determining a situation in which garments are lumped during a process of conveying or folding the garments, may effectively prevent damage to the lumped garments and related components, and may significantly reduce the time for which the operation of the folding machine is stopped by accurately specifying the position at which the garments are lumped and then notifying a user of the position to allow the user to take an immediate action.