The invention discloses an empennage adjusting mechanism. The empennage adjusting mechanism comprises a steering engine unit, an empennage fixing piece and an empennage unit, wherein the steering engine unit comprises a pitching steering engine, a yawing steering engine and pull rods. A limiting groove is formed in the empennage fixing piece, and the empennage unit comprises an empennage central rod, an empennage central ball head and an empennage movable piece; and the empennage movable piece is connected with the empennage central rod in a surrounding mode, the empennage central rod penetrates through the empennage central ball head, the empennage central ball head is located in the empennage fixing piece, the empennage central rod is limited by the limiting groove, the pitching steering engine is connected with the empennage movable piece through the corresponding pull rod, and the yawing steering engine is connected with the empennage central rod through the corresponding pull rod. According to the empennage adjusting mechanism, the U-shaped empennage fixing piece with the limiting groove is provided, an empennage is moved through the steering engines, the movable direction of the empennage is limited on the basis of the central rod and the limiting groove, the steering engines are installed through an installing plate, and thus control over the empennage can be achieved under the condition that the influence is not caused to the overall structure of an aircraft.