An indirect thermal desorption device with two-section screw conveyors, includes: an upper skid and a lower skid below the upper skid. An upper layer thermal desorption chamber, a feeding hopper, an feed airlock, an air pre-heater, a blower; a first quench spray tower, a second quench spray tower, a demister and an induced draft fan are provided in the upper skid. A lower layer thermal desorption chamber, an activated carbon filter tank, a combustion chamber, a discharge hopper and an discharge airlock are provided inside the lower skid. A first screw conveyor is provided in the upper layer thermal desorption chamber, and an upper layer fume jacket is covered on the upper layer thermal desorption chamber. A second screw conveyor is provided in the lower layer thermal desorption chamber, and a lower layer fume jacket is covered on the lower layer thermal desorption chamber.