The invention provides a back pressure steam turbine start exhaust recovery system which comprises a hybrid start exhaust heater, a start exhaust recovery hot-water tank, a start exhaust pipeline, a low-temperature saline removal pipeline, a high-temperature saline removal pipeline and a saline removal box; the hybrid start exhaust heater is connected with a back pressure steam turbine through the start exhaust pipeline and is connected with the start exhaust recovery hot-water tank through the high-temperature saline removal pipeline, and the saline removal box is connected with the hybrid start exhaust heater through the low-temperature saline removal pipeline. By the arrangement, problems about working-medium wastage, 'visual pollution, noise pollution and the like existing in starting of the back pressure steam turbine are solved, working mediums and heat are recovered, resources are saved, economy of power plants is improved, and remarkable environment friendly and social benefits are produced.