A fluid guiding cover is adapted to be assembled to a casing. The fluid guiding cover includes a first plate, a second plate, and a third plate. The first plate has a main body portion and a sidewall portion, wherein the main body portion is detachably fixed on the casing and stretches over a channel of the casing. The sidewall portion is connected to the main body portion and located in the channel. The second plate is rotatably disposed on one side of the sidewall portion, wherein the second plate is located in the channel and configured to abut against or separate from a bottom surface of the casing. The third plate is rotatably disposed on one side of the sidewall portion and disposed in parallel with the second plate, wherein the third plate is located in the channel and configured to abut against or separate from the bottom surface.