The invention discloses a filter net blockage detection method of an air supply device and the air supply device using the same. The air supply device comprises an air inlet, an air outlet, an air channel, a fan or an air wheel, a fan motor and an air filter net, wherein the air filter net is arranged on the air channel; and the fan motor drives the fan or the air wheel to rotate, so that air enters the air channel from the air inlet and passes through the air filter net and is output from the air outlet. The air supply device is characterized in that the fan motor is used as an air amount detection element; when the detected air amount is lower than a set air amount, whether the air filter net is blocked is judged and a signal is output for warning; no hardware needs to be added; and the installation is convenient and the cost is low.