The invention discloses a double-layer cast iron pan casting process and relates to cookers in the field of daily life. Two iron alloys with different compositions are selected, melted and cast to form a double-layer composite cast ion pan. The cast ion pan is cast in twice, materials adopted for casting in twice are different, the inner layer contains more trace elements and enhancing components, and therefore the strength and rust resistance of the inner layer are substantially enhanced while the inner layer which is in contact with food provides necessary iron and zinc elements. Meanwhile, after casting of the inner layer and outer layer is finished, atoms of same components and different components between the inner layer and the outer layer can mutually migrate and merge by means of heat preservation for a certain time, and finally the strength and uniformity of the pan are improved.