The invention relates to a method for preparing a perovskite solar cell with high short-circuit current and high conversion efficiency, and a product, and belongs to the technical field of photovoltaics. The method comprises the following steps: firstly, a layer of methyl iodide amine is spin-coated on a hole transport layer; and then a hot precursor solution of MAPbI3-xClx is spin-coated on the methyl iodide amine layer; when the hot MAPbI3-xClx precursor solution is dropped onto the methyl iodide layer, the spin-coated methyl iodide layer is dissolved again, so that the concentration of iodine at the interface between the hole transport layer and an MAPbI3-xClx perovskite light absorbing layer is greater than that at other positions of the MAPbI3-xClx perovskite light absorbing layer; after annealing crystallization at the later stage, an iodide ion concentration gradient is formed on the MAPbI3-xClx perovskite layer at the interface between the hole transport layer and the MAPbI3-xClx perovskite light absorbing layer, and such a halogen concentration gradient increases the position of the perovskite conduction band, thereby facilitating the transport of holes, and further increasing the short circuit current and the conversion efficiency. The method is simple and easy to operate, can be directly promoted in large scale in industrial production, and has a potential application value in solar cells.