The utility model discloses a variable speed seat assembly device installs on vehicle frame for control the selector rod of vehicle, including installing the base seam on vehicle frame, transversely be equipped with the variable speed axle of shifting in the base seam, the variable speed of shifting gears hub connection has the gear change lever who upwards extends the setting, the variable speed of shifting hub connection has and is located the transposition rocking arm of base seam lateral part, the transposition rocking arm is connected with the little pull rod of shifting, the little pull rod of shifting is connected with the selector rod, the tip of the variable speed of shifting axle still is connected with the return board, the return board with wear to be equipped with the return axle between the base seam, the epaxial cover of return is equipped with and is located the return board with return spring between the base seam. The utility model discloses an about the transposition structure of shifting around, accord with human custom hard, shift transposition stroke and banking reduce greatly, control lightly laborsavingly, the compactness is arranged to while spare part, occupation space is little.