The invention discloses a device and a method for drying lignite in a combined mode through microwave and hot air, and belongs to the technical field of lignite drying equipment. The device comprisesa feeding device, a vibration transmission mechanism, a hot air generating device, microwave generating devices, a drying cavity, a temperature measuring system and a tail gas treatment device, wherein the feeding device comprises a feeding hopper and a spiral feeder, the hot air generating device comprises a blower and a hot blast stove; more than one microwave generating device and more than oneexhaust port are arranged above the drying cavity; a heat preservation layer and a metal shell capable of shielding microwaves are arranged in the cavity, the vibration transmission mechanism is connected with a vibration motor outside a cavity, and the tail end of the vibration transmission mechanism is provided with a drawable baffle and a discharge port. The method for drying lignite in a combined mode through microwave and hot air comprises the following steps of crushing raw coal, and carrying out the sieving treatment; carrying out the feeding through the spiral feeder, starting the hotair generating device and the microwave generating device; carrying out the vibration and conveying through the vibration transmission mechanism, drying the brown coal in the microwave drying cavitythrough microwave hot air, and obtaining a finished product through drying, and collecting the finished product in the finished product coal bin through a movable baffle. The device is simple in structure, low in investment cost, small in occupied area, high in operation efficiency and capable of realizing continuous production; the method for drying in a combined mode through the microwave and the hot air is capable of improving the heat efficiency of materials and high in drying speed, capable of recycling waste heat, high in energy utilization rate, capable of reducing energy consumption, and environment-friendly.