A cover actuating and self-locking device. A fixed end of a first lever (1) is hingedly connected to a fixed hinging point (J1). A bottom end of a third lever (3) is hingedly connected to a cover hinging point (J4), and a stopping hinge shaft is slidably inserted into a stopping groove (103). When the first lever (1) is rotated, a second lever (2) can push the stopping hinge shaft to slide from a free end of the stopping groove to a locking end (S), and a third lever (3) can push a cover (4) to move from an upper locking position to a lower locking position. At the lower locking position, when a line connecting a top-end hinging point and a bottom-end hinging point of the third lever (3) rotates along a locking rotation direction (w) so as to be aligned with a plane of a top surface of the cover (4), the angle of rotation (a) is not greater than 90 degrees. Further provided is a beverage brewing device and a beverage brewing system. The device has a simple structure, is easy to process and manufacture, and has reliable work performance. The invention has a low cost and can be used in beverage brewing devices.