The main oil pump, emergency governor, axial displacement transmitter, thrust support combined bearing and other parts of the governing system are installed in the front bearing block at the front end of the steam turbine. The front bearing seat is supported by the front seat frame. There are longitudinal keys on the seat frame along the center line of the steam turbine. When the unit is heated and expanded, it can slide forward along the longitudinal key. The front bearing seat is connected with the front cylinder by cat claws, and there are Vertical Keys in the vertical direction to ensure that the center of steam turbine will not change during expansion.