Abstract: Thermal electricity conversion based on the heat extracted from underground coal fires, comprising a coalfield fire area (1), coalfield drill holes (2), underground heat conduction pipelines (3) and a heat conduction container (4) which is provided with a pressure relief device (5) thereon and further comprises thermoelectric power generation chip sets (6) and a storage battery (7), wherein the thermoelectric power generation chip sets (6), having cold-side radiator pipes (8) provided on outer sides thereof, are provided on an outer side wall of the heat conduction container (4). The thermoelectric power generation chip sets in the invention are directly attached on the heat conduction container, so that the system is simple in structure without redundant components and high in heat conduction efficiency.