The utility model provides an urea pyrolysis system ammonia system and boats and ships for boats and ships relates to boats and ships pyrolysis system ammonia technical field. Urea pyrolysis system ammonia system includes for the boats and ships: pyrolysis oven, urea solution dosage distributor, diesel combustion ware. The pyrolysis oven is used for carrying on the operation of pyrolysis system ammonia, and the pyrolysis oven has first entry and a the second entrance, and first entry is used for infeeding urea solution, and it is required hot -blast that the second entrance is used for infeeding pyrolysis system ammonia, urea solution dosage distributor is used for storing and distributes urea solution, and urea solution dosage distributor passes through pipeline and first entry intercommunication, the diesel combustion ware is used for the place as the diesel combustion operation, and the produced high temperature flue gas of diesel combustion is used for importing the second entranceto a first heat source for regarding as the operation of pyrolysis system ammonia. This boats and ships for urea pyrolysis system ammonia system can provide effectively, the abundance the heat source, can improve ureal decomposition efficiency, reduce economic expenditure, ensure environmental security, great market spreading value has.