The invention discloses an adsorption type air dryer and a drying method. The air dryer comprises an adsorption tower and a regeneration tower; the drying method is characterized in that gas with impurities flows into the adsorption tower from a gas inlet of the adsorption tower to be dried and filtered, part of the dried and filtered gas is fed into a wind use unit from a gas outlet, the other part of the dried and filtered gas enters the regeneration tower by a regeneration passage, the impurities in the regeneration tower are cleaned, and the gas flows out of a vent after flowing through the regeneration tower; a control valve is connected with the gas outlet by a pipeline, a gas control combination valve is connected with the gas inlet and the vent by pipelines, and the gas inlet and the vent are switched by controlling the gas control combination valve and the control valve, so that the adsorption tower and the regeneration tower are switched, and the adsorption tower is enabled to continuously feed the dried and filtered gas into the wind use unit from the gas outlet. The air dryer is simple in structure, connection nodes are fewer, maintenance times and costs can be reduced, the operation is simple and quick, and errors are not easily caused.