A method for fabricating a collagen bio-ink includes steps as follows. A first component is provided, wherein the first component is to fill a collagen powder to a first syringe. A second component is provided, wherein the second component is to fill a neutral solution or an acid solution to a second syringe. A mixing step is performed, wherein the first syringe is connected to the second syringe with a Lure lock connector and pushing back and forth to mix the first component and the second component to form a hydrogel and become a collagen bio-ink.