Gas turbines cannot be directly reversed, and the astern operation of gas turbines still requires additional power transmission equipment to be achieved. To compensate for this deficiency, the application of turbine-blade-tip turbine in gas turbines was proposed. Turbine-blade-tip turbines have the characteristics of extremely low solidity and extremely high diameter-span ratio. Compared with conventional turbine blades, the capacity of turbine blades to restrain gas flow is greatly weakened, the separation flow is obvious when going astern, resulting in low efficiency. For the control problem of low solidity turbine-blade-tip turbines separation flow, a splitter blade control strategy is selected to suppress the separation flow. Adding a splitter blade between original rotor blades effectively improves the ability of rotor blades to restrain gas flow, significantly reduces separation phenomena, and significantly improves efficiency. As the axial chord length of the splitter blade shortens, the inhibitory effect on the separation flow decreases, and the ability of splitter blades to improve the efficiency gradually descends.