The invention provides a method for treating soil organic matter and mercury combined contamination. The method comprises the steps that firstly, weeds and stones on the surface of a contaminated plot are removed, and the soil is pressed by a rolling compaction device; the contaminated plot is covered with a low-density polyethylene film, and the low-density polyethylene film is tightly pressed through the rolling compact device; vertically downward drilling is conducted on the center of the contaminated plot through a drilling machine, and a cylindrical pore channel is formed; single-head heating rods are vertically inserted into the four corners of the contaminated plot downwards; the cylindrical pore channel is sequentially connected with a vacuum pump, a drying device, an activated carbon adsorption device and an exhaust cylinder through a pipeline; and the vacuum pump and the heating rods are started, and organic matter and mercury in the soil are separated under the effect of thermal radiation and vacuum pumping. By means of the method, it is not necessary to introduce air continuously, the separation process is enhanced through the thermal radiation and high negative pressure effect, and the efficient in-site repair is achieved.