A fluid cleaning apparatus includes a driving assembly including a motor, a gear clutching assembly, a moving assembly, a swaying spray assembly, a sensing assembly, and a controlling module. The fluid cleaning apparatus integrates functions of movement actuation and spraying angle adjustment with the motor and achieves versatile spraying angles for spray-cleaning with apparatus configuration convertible between swaying motion and ceased swaying motion and/or between moving motion and ceased moving motion. Besides, self-propelled movement, spraying pressure modulation, and spraying angle adjustment can be controlled by the control module or manually remotely controlled by a user. Since the fluid cleaning apparatus of the present application saves the conventional installation cost and space needed, as well as resources consumed, for cleaning the bottom of an object to be cleaned, the fluid cleaning apparatus can be extensively applied to multiple fields.