The invention relates to a method for preparing hydrocarbon-rich combustible gas through the gasification of combustible solid waste. The method can be used for preparing hydrocarbon-rich high-quality combustible gas. The system is composed of a fluidized bed gasification reactor, a cyclone melting furnace, a water vapor reforming reactor, a super-heater, an economizer, a hydrocarbon synthesis reactor, a heat pipe heat exchanger, a bag filter, a gas scrubbing tower, a dehydration tower, an induced draft fan, a compression device, a gas storage tank, an air separation device, and the like. The method adopts a heat conversion technology especially aiming at high-efficiency and clean utilization of combustible solid waste as an energy. With the method, combustible gas rich in hydrocarbon gas can be prepared, contents of tar and carbon particles in combustible gas can be effectively reduced, metal resources in combustible solid waste can be recovered, and near-zero discharging of pollutants such as dioxin can be realized. With the system, gas preparing cost is reduced with a maximal extent, such that effective recovering and utilization of resources are realized. An overall thermal efficiency is high, and environment pollution is low. The method is highly economic, safe, and reliable.