A propulsion system assembly includes a propeller and a motor configured to drive the propeller to rotate. The propeller includes one of a first body and a second body. The motor comprises the other one of the first body and the second body. The propulsion system assembly also includes a locking mechanism configured to detachably connecting the first body and the second body. The locking mechanism includes a locking member and a position limiting lock catch. The locking member is configured to lock the first body and the second body. The locking member includes locking parts located at at least two sides of the locking member. When the locking parts of the locking member rotate to a locking position, the position limiting lock catch is mounted to a side of the locking parts, to restrain the locking member from rotating relative to the first body.