The invention provides a light gas turbine gas inlet adjusting auxiliary device. The light gas turbine gas inlet adjusting auxiliary device comprises a gas inlet pipe and a change-over valve. The sametransverse section of the gas inlet pipe is provided with a first opening and a second opening. A first branch pipe and a second branch pipe communicate with the gas inlet pipe through the first opening and the second opening correspondingly. The change-over valve is arranged at the axial tail end of the gas inlet pipe and comprises a rotation rod. A closing plate is arranged at the closed end ofthe gas inlet pipe. The rotation rod penetrates through the closing plate, the rotation rod stretching to one end in the gas inlet pipe is connected with a flow baffle through a support rod, and thearea of the flow baffle is larger than the opening area of the first opening and the second opening. According to the light gas turbine gas inlet adjusting auxiliary device, equipment is reasonably utilized, and the heat efficiency of a gas turbine is improved.