The invention discloses a fuel gas-steam combined circulation unit dewatering recycling system. A drain flash tank, a dewatering receiving header, a water discharging mother pipe, a water draining pipeline, a temperature lowering water pipeline, a steam discharging pipeline, an overflow pipeline, a water discharging pipeline, a pollution discharging unit and a steam condenser are included; the drain flash tank is connected with the temperature lowering water pipeline, the steam discharging pipeline, the dewatering receiving header, the overflow pipeline and the water discharging mother pipe; the drain flash tank is connected with a hot well of the steam condenser through the water discharging mother pipe and a dewatering recycling pipe; the overflow pipeline is connected with the pollutiondischarging unit; the water discharging mother pipe is connected with the water draining pipeline which is connected with the pollution discharging unit; the dewatering receiving header is connectedwith a dewatering pipe; and the dewatering recycling pipe is connected with the water discharging pipeline which is connected to a sewage recycling treatment system. The fuel gas-steam combined circulation unit dewatering recycling system solves the problems of work medium waste, hot pollution and random discharging and random draining in the processes of starring and running of a fuel gas-steam combined circulation unit, resources are saved, the economical efficiency of a power plant is improved, and obvious environment-friendly social benefits are generated.