A shower door assembly comprising a top frame and a bottom frame; the shower door assembly comprising: a first movable glass door having at least two first pulleys (101, 102) at a top end of the first movable glass door and at least two second pulleys (103, 104) at a bottom end of the first movable glass door; and a second movable glass door having at least two third pulleys (201, 202) at a top end of the second movable glass door and at least two fourth pulleys (203, 204) at a bottom end of the second movable glass door; wherein the first and third pulleys are slidably engaged with the top frame, and the second and fourth pulleys are slidably engaged with the bottom frame; wherein each of the first and second pulleys comprises a pulley seat connectable to the top/bottom frame, a pulley bracket having a pulley wheel and receivable in the pulley seat, a first pressing block connected with the pulley bracket and able to press the pulley bracket to move, and a first elastic member provided between the pulley bracket and the pulley seat; wherein each of the third and fourth pulleys comprises a pulley seat connectable to the top/bottom frame, a pulley bracket having a pulley wheel and receivable in the pulley seat, a second pressing block connected with the pulley bracket and able to press the pulley bracket to move, and a second elastic member provided between the pulley bracket and the pulley seat of each of the third/fourth pulleys: wherein at least one of the first pulleys (101, 102) is located between the third pulleys (201, 202) and pressed by a first pressing means provided on the third pulleys, and at least one of the second pulleys (103, 104) is located between the fourth pulleys (203, 204) and pressed by a second pressing means provided on the fourth pulleys; wherein each of the first and second pressing means comprises a pressing bar having a groove, and an elongated rubber received within the groove and in contact with the pulley wheel of the respective pulley; and wherein when the first or the second movable glass door is moved, the elongated rubbers will apply a friction force onto the pulley wheels (120, 220) of the other movable glass door to drive the latter to roll along rails (301, 302) of the top frame and the bottom frame such that the other glass door is actuated to move during the movement of said first or second glass door. a first movable glass door having at least two first pulleys (101, 102) at a top end of the first movable glass door and at least two second pulleys (103, 104) at a bottom end of the first movable glass door; and a second movable glass door having at least two third pulleys (201, 202) at a top end of the second movable glass door and at least two fourth pulleys (203, 204) at a bottom end of the second movable glass door; wherein the first and third pulleys are slidably engaged with the top frame, and the second and fourth pulleys are slidably engaged with the bottom frame; wherein each of the first and second pulleys comprises a pulley seat connectable to the top/bottom frame, a pulley bracket having a pulley wheel and receivable in the pulley seat, a first pressing block connected with the pulley bracket and able to press the pulley bracket to move, and a first elastic member provided between the pulley bracket and the pulley seat; wherein each of the third and fourth pulleys comprises a pulley seat connectable to the top/bottom frame, a pulley bracket having a pulley wheel and receivable in the pulley seat, a second pressing block connected with the pulley bracket and able to press the pulley bracket to move, and a second elastic member provided between the pulley bracket and the pulley seat of each of the third/fourth pulleys: wherein at least one of the first pulleys (101, 102) is located between the third pulleys (201, 202) and pressed by a first pressing means provided on the third pulleys, and at least one of the second pulleys (103, 104) is located between the fourth pulleys (203, 204) and pressed by a second pressing means provided on the fourth pulleys; wherein each of the first and second pressing means comprises a pressing bar having a groove, and an elongated rubber received within the groove and in contact with the pulley wheel of the respective pulley; and wherein when the first or the second movable glass door is moved, the elongated rubbers will apply a friction force onto the pulley wheels (120, 220) of the other movable glass door to drive the latter to roll along rails (301, 302) of the top frame and the bottom frame such that the other glass door is actuated to move during the movement of said first or second glass door.