The invention discloses a method combining sulfur and exhaust gas to produce acid. The method includes the steps of: hydrogen sulfide combustion, first washing, second washing, third washing, acid mist removal, drying, sulfur combustion, conversion and the like. The method mainly solves the problems that: during single use of an acid preparation method in the prior art, the equipment utilization rate is not high, and insufficient exhaust gas can result in shortage of system load, an electric furnace needs to be turned on for heating to compensate heat, and accordingly the system operation fluctuates, and the power consumption cost increases. By combining two acid production methods, the utilization rates and work efficiency of two devices can be improved, meanwhile the production cost is reduced, and the service life of equipment is prolonged. The method has the advantages of low cost and high efficiency.