The invention discloses an automatic docking fill-drain connector pose compensation mechanism for a carrier rocket. The mechanism comprises a ground connector panel (1) and a moving platform (2) parallel to the ground connector panel (1). Four moving branch chains (3) are distributed in a matrix between the moving platform (2) and the ground connector panel (1) and movably connect the moving platform (2) with the ground connector panel (1). By means of the pose compensation mechanism, automatic and accurate alignment between a ground docking device and a rocket body in the docking and follow-up process can be achieved.