The invention relates to a saturation method of a graphite boat, and belongs to the technical field of solar cells. The saturation method comprises a fake-piece saturation stage and an empty-boat saturation stage. Saturation is performed through the combination of two ways, so that the Rsh of battery pieces is guaranteed and wafer range and inter-wafer range are reduced. The using effect of the saturated graphite boat is effectively improved; film thickness range of silicon wafers in the graphite boat is reduced; the stability of the graphite boat is improved, so that the surface color difference of the silicon wafers is reduced.