The invention provides a system and method for simultaneous dry-method hydrogen production from catalytic methane decomposition and carbon dioxide separation. The system comprises a methane decomposition system (I), a catalyst regeneration system (II), a gas solid separation system (III), and a gas circulating system (IV), wherein the methane decomposition system (I) is used for preparing and purifying hydrogen; the catalyst regeneration system (II) is used for receiving the deactivated catalyst, and the methane mixed gas, which is not completely converted, from the methane decomposition system (I), and causing the deactivated catalyst and the methane mixed gas to react with an oxide to eliminate carbon decomposition and provide the heat needed by the methane decomposition system (I); the gas solid separation system (III) is used for receiving and separating the solid particle and conveyed gas from the catalyst regeneration system (II) and the methanol decomposition system (I), and conveying the separated solid particle and conveyed gas into corresponding reactors; the gas circulating system (IV) is used for receiving the carbon dioxide gas from the gas solid separation system (III), collecting partial carbon dioxide gas, and returning partial carbon dioxide and decomposed gas into a reduction reactor (7). By adopting the system disclosed by the invention, the full-component graded conversion of the methanol is achieved.