The invention relates to an application of ammonia to an SOFC battery and an application apparatus of the application. The application is characterized by comprising a step 1 of ammonia gas heating and a step 2 of ammonia gas decomposition. A heating and decomposition apparatus comprises a first pressure-reducing valve, a first solenoid valve, a high-temperature-exhaust-gas discharging cylinder, a heat exchange chamber, an annular high-temperature-resistant stainless-steel coil pipe, a temperature inductor, a safety vent valve, a gas-mixing chamber, a decomposition chamber, a spiral airway structure, gas dispersing and burning nozzles with igniters, a second solenoid valve, a second pressure-reducing valve, a third solenoid valve, a fourth solenoid valve, and a drying and purifying devices. The application has advantages that ammonia is free of carbon and can be used as fuel, and therefore, the 'carbon poisoning' phenomenon of an SOFC catalyst is completely overcome; during a hydrogen production process through ammonia gas decomposition, no vapor is required, so that requirements for devices and water resources are reduced; and fuel gas heating is adopted, so that the SOFC battery can be applied to a mobile device. Waste heat is utilized, and energy is effectively saved.