Abstract: The invention provides a close space annealing method and a method for preparing a perovskite film or a solar cell. The method includes: placing a substrate coated with the perovskite precursor film on a hot plate, the hot plate being in direct contact with the back face of the substrate; controlling the evaporated amount and residual amount of the solvent in the perovskite precursor film by controlling the temperature of the hot plate and the heating duration, so that the perovskite materials are crystallized into perovskite grains to form a perovskite intermediate-phase film; placing the perovskite intermediate-phase film on the permeable membrane with the back face of the substrate facing upward, continuing with heating, so that adjacent perovskite grains merge with each other; and raising the temperature of the hot plate and continuing with heating so that the perovskite grains form a perovskite light-absorbing layer.