The invention discloses a water-based acrylic modified saturated polyester, a method for preparing the same and water-based baking aluminum powder paint. Water-based acrylic resin, a water-based saturated polyester resin composition, epoxy resin and amino resin used as film forming materials and unctuous aluminum powder as a coloring material are prepared and are applied to a water-based system, so that the production cost is significantly reduced. The water-based acrylic modified saturated polyester uses water as a diluent so that the water-based acrylic modified saturated polyester is nonpoisonous, tasteless, pollution-free, non-waste, non-flammable and non-explosive, and the VOC content is smaller than 50 to ensure the environmental protection and fire safety and guarantee the health of workers; besides, the formed paint film has the advantages of high hardness, scratch resistance, strong adhesive force, salt mist resistance, salt water resistance, acid and alkali resistance, waterresistance, oil resistance, ultraviolet light resistance, aging resistance, low temperature resistance, damp heat resistance and sweat resistance, can be repeatedly used on the surface of a (water-based, oil-based) old paint film, cannot cause paint film damage, has ultra-strong paint film flexibility and the like.