A vacuum cleaner system includes a docking station and a mobile vacuum cleaner. The docking station includes a charging stand and a parking plate. The parking plate is connected to the charging stand, and formed with two position-limiting slots. The mobile vacuum cleaner includes a working machine body and two transmission wheels. The transmission wheels are rotatably arranged on the working machine body for traveling the working machine body. When the transmission wheels are moved into the position-limiting slots, respectively, the mobile vacuum cleaner presses the parking plate by a gravity of the mobile vacuum cleaner through the two transmission wheels.