Abstract: Taking a thermal power plant as an example, this paper introduces the urea hydrolysis ammonia production system, analyzes the operating conditions of the denitration and hydrolysis reactor system, and solves the problems of large pressure fluctuation and poor operating stability of the hydrolysis reactor by analyzing various parameters, optimizing the operation mode and adjusting the automatic steam control valve of the hydrolysis reactor, so as to ensure the sufficient ammonia supply of the unit and control the environmental protection data exceeding the standard.