Abstract Ammonia is a compound of nitrogen and hydrogen with the formula NH3. It is a colorless gas with a characteristic pungent smell. Several processes have been invented for optimum production of ammonia. Now-a-days, Haber process is a mainly process for Ammonia production in which the reaction between nitrogen and hydrogen done in the presence of an iron catalyst to form ammonia. In our work, simulation of ammonia synthesis process is done on Aspen Hysys V8.8. By using 333.1 kmole/h of steams, 100 kmole/hr of nitrogen, we have produced 74.62 kmole/hr ammonia. It has also been found that ammonia production increases with the rise of pressure & mass flow of steam& decrease of the temperature of the feed of nitrogen.