The invention discloses a steam-extracting and heat-supplying power station system with complete thermoelectric decoupling and a working method. The steam-extracting and heat-supplying power station system is a power station system with steam extraction and heat supply and with in-series connection of two-stage bypasses. The steam-extracting and heat-supplying power station system and the working method disclosed by the invention have the advantages that by modification of the heat-supplying power station system of the original middle reheating unit, not only can the heat-supplying safety of regions at the heat-supplying peak period in winter be guaranteed, but also greatest reduction of the power-generation load of a steam turbine is allowed, so that the wind-electricity receiving capability can be greatly improved and the purpose of complete thermoelectric decoupling can be achieved. The scheme disclosed by the invention has the advantages of convenience in implementation, obvious effect, low investment cost and the like.