The invention discloses a method for selecting flexible graphite at a position of a bearing block of a gas turbine. The method comprises the following steps: selecting an adjusting washer with a preset thickness according to the thickness of the flexible graphite and amount of compression during actual assembling of the flexible graphite; successively mounting the adjusting washer and a tube connecting seat assembly into mounting holes of the bearing block of the gas turbine and tightening the tube connecting seat assembly, wherein the bearing block of the gas turbine is provided with a rear mounting side, the tube connecting seat assembly comprises a mounting section and an extension section which extends from the mounting section, the mounting section comprises a connecting portion, theconnecting portion and the tail end surface of the mounting section are arranged in a step shape, the periphery of the connecting portion is rotatably connected to the inside of the mounting hole by threads, and the adjusting washer is sandwiched between the first end surface of the connecting portion along the axial direction and the inner wall of the mounting hole; and estimating an included angle alpha between the axis of the extension section and the axis of the bearing block of the gas turbine in the same plane, and controlling the turning amount of a first end surface along the axial direction according to the included angle alpha so that the turned tube connecting seat assembly meets the amount of compression of the flexible graphite during actual assembling and meanwhile the extension section faces the rear mounting side.