The invention discloses soil purifying equipment based on heterotopic thermal desorption. The equipment comprises a cylindrical movable outer cylinder, and a cylindrical inner furnace body fixedly installed, wherein the movable outer cylinder coaxially and movably sleeves the outer side of the inner furnace body. The equipment further comprises an outer cylinder driving device; the outer cylinderdriving device can drive the movable outer cylinder to displace and rotate up and down along the axle; a cylindrical furnace wall of the inner furnace body is a heat conducting thin wall structure; the internal of the cylindrical furnace wall is a combustion cavity; an annular columnar soil thermal desorption cavity is formed between the outer wall of the cylindrical furnace wall and the movable outer cylinder; and heat in the combustion cavity is transferred to the soil thermal desorption cavity through the cylindrical furnace wall. The movable outer cylinder is intermittently rotated forwards and reversely back and forth along the axle, so that a soil source in a spiral cavity is always located in a fluffy rolling state, and the soil source is uniformly heated; and after the soil sourcein the spiral cavity is heated, volatile pollutants in soil are gasified to generate a thermal desorption effect.