NOVELTY - A hydrogen is prepared by (A) preparation of parts of a hydrogen preparation device; (B) assembly of hydrogen preparation device; and (C) hydrogen preparation. Round sheet micro-crystal ceramic membrane is prepared. Reaction chamber has reaction hole at bottom, where shell with drain port is provided close to bottom sidewall. Partition board is provided with liquid gas hole. Upper cover having water injection port and hydrogen outlet on top are respectively produced according to size of micro-crystal ceramic membrane. End face of micro-crystal ceramic membrane is close to outer diameter.    USE - Method for preparing hydrogen.    ADVANTAGE - The method obtains high purity hydrogen. It is simple, and is convenient to carry and operate. The method is safe, has low in cost and high hydrogen yield, and is assorted with small fuel cell.    DETAILED DESCRIPTION - Hydrogen is prepared by (A) preparation of parts of a hydrogen preparation device; (B) assembly of hydrogen preparation device; and (C) hydrogen preparation. Round sheet micro-crystal ceramic membrane is prepared. Reaction chamber has reaction hole at bottom, where shell with drain port is provided close to bottom sidewall. Partition board is provided with liquid gas hole. Upper cover having water injection port and hydrogen outlet on top are respectively produced according to size of micro-crystal ceramic membrane. End face of micro-crystal ceramic membrane is close to outer diameter stacking on bottom surface of a cavity of reaction chamber in dry environment by waterproof alkali resistant sealing adhesive. After free leakage is detected, lithium ingot and a spring are placed from bottom to top. Reaction chamber is sealed and fixed under partition board. Partition board is sealed between cavities formed by shell and the upper cover. Cavities form an upper cavity and lower cavity. When hydrogen is prepared, drain port is blocked by drain stopper. Hydrogen outlet is connected on hydrogen application device. Pure water is injected in water injection port closely. Pre water flows into lower cavity from a liquid gas hole on partition board. When level of lower cavity is higher than bottom of reaction chamber and lower than partition board, the water injection port is blocked by water injection stopper. Hydrogen is discharged to upper cavity through liquid gas hole of partition board and flows to hydrogen application device by hydrogen outlet. When hydrogen preparation is stopped, drain stopper is opened, pure water device is discharged clearly and hydrogen preparation is stopped.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating a hydrogen preparation device.