The invention relates to a manufacturing method of a stainless steel valve. At least one of the valve seat, valve cover, valve core and valve cap is made of a stainless steel casting process. The process comprises the following steps: (1) preparing a resin sand mould: preparing an inner core and an outer mold from resin sand according to the shape and appearance of the inner hole of a product; (2) coating: coating a high temperature resistant paint on the outer surface of the inner core and the inner surface of the outer mold and drying; (3) pouring: molting steel, injecting the molten steel into a cavity formed by the space between the inner core and the outer mold; (4) opening the mold: cooling, opening the mold and taking out the stainless steel casting; and (5) cleaning the casting and machining to obtain the stainless steel product. By changing the preparation process, the stainless steel material can be used in the preparation of the valves, such as stainless steel stop valve and water valve; the process is simple and practical; and the obtained product has stable quality, does not have leakage due to stress cracks, and is environment-friendly and resistant to corrosion.