The invention discloses a low-pressure steam turbine air inlet guiding device. The low-pressure steam turbine air inlet guiding device comprises a shell. An inner cavity is fixedly arranged in the shell. A through cavity which penetrates through the front and rear sides is formed in the position, located in the shell, of the inner side of the inner cavity. An embedded block is fixedly arranged between the front end wall and the rear end wall of the through cavity. A power cavity is fixedly arranged in the embedded block. The outer side of the through cavity is provided with an annular transmission cavity located in the shell. A driving bevel gear is arranged in the transmission cavity. The lower end face of the driving bevel gear is fixedly provided with a rotary rod. The rotary rod rotates to penetrate through the transmission cavity and extend into the inner cavity to be connected with the rear end wall of the inner cavity in a rotating fit mode. The outer surface of the rotary rod is fixedly provided with an intermediate chain wheel. The side, close to the power cavity, of the driving bevel gear is engaged with a driven bevel gear. The low-pressure steam turbine air inlet guiding device is simple in structure and convenient to use, achieves the high-efficiency air inlet guiding function through an angle adjustable air guiding working method and then improves the working efficiency of a steam turbine.