The invention discloses a waste heat steam turbine generator offshore grid-connected operation control and stabilizing method, and relates to waste heat steam turbine generator offshore grid-connectedoperation control technologies. The method comprises the steps that S1, a waste heat generator is connected to a grid for power generation according to the maximum output power capacity of the wasteheat generator, a gas turbine generator located in the same power station as the waste heat generator is connected to the grid for power generation in a constant active power output mode, and gas turbine generators of the rest of power stations are connected to the grid for power generation in an active power proportional operation mode; and S2, grid reference frequency sampling points are determined, and the frequency stability of the whole grid is achieved through frequency increase and decrease adjustment of the gas turbine generators. The waste heat steam turbine generator of the power station can be smoothly integrated into the grid and operated stably and safely, and the good energy saving and emission reduction effects and economic benefits are achieved.