The invention relates to a system and a method for preparing hydrogen-rich gas and calcium carbide. The system comprises a mixing forming unit, a high-temperature pyrolysis unit, a catalytic reforming unit, a transformation and decarbonization unit and a calcium carbide smelting unit, wherein the mixing forming unit comprises a coal dust inlet, a calcium-based raw material inlet, an adhesive inlet and a briquette outlet; the high-temperature pyrolysis unit comprises a briquette inlet, a raw gas outlet and a high-temperature active pellet outlet; the catalytic reforming unit comprises a raw gas inlet and a synthetic gas outlet; the transformation and decarbonization unit comprises a synthetic gas inlet and a hydrogen-rich gas outlet; the calcium carbide smelting unit comprises a high-temperature active pellet inlet and a calcium carbide outlet. The method for preparing the hydrogen-rich gas and the calcium carbide by virtue of the system comprises the following steps: performing mixing forming and pyrolysis on coal dust and a calcium-based raw material to obtain raw gas, and performing catalytic reforming, transformation and decarbonization to obtain the hydrogen-rich gas; smelting obtained high-temperature active pellets to obtain the calcium carbide. According to the system and the method, the heat of pyrolysis gas is utilized, and the pyrolysis gas with complex components is also transformed into the hydrogen-rich gas.