The invention discloses a compressed air drying device based on a vortex tube refrigeration technology, belonging to the technical field of air drying. The compressed air drying device comprises an air compressor, an air-liquid heat exchanger, an air cooler, a high-pressure air storage tank, a high-pressure dehumidifier, a first control valve, a nozzle, a pore plate, a vortex tube, a second control valve, a high-pressure liquid storage tank, a first throttling valve, an intermediate heat exchanger, a solution heater, a normal-pressure regenerator, a normal-pressure liquid storage tank, a high-pressure solution pump, a solution cooler, a third control valve and a dry air outlet. The invention further discloses a working method of the drying device. The drying device has the following beneficial effects of improving the energy utilization efficiency of the compressed air drying system, enhancing humidifying and regenerating effects, effectively reducing the moisture content of a compressed air outlet, and improving the refrigerating efficiency and the energy utilization rate of the vortex tube. The working method of the compressed air drying device based on the vortex tube regeneration technology is simple in steps and is energy-saving and environment-friendly.