Fossil fuels reserves are getting lesser and lesser nowadays. In Malaysia, the price of gasoline and diesel keep shooting up leaving scientist and engineer in search for a new substitution fuel. Natural gas such as Hydrogen and SYngas are the renewablefuel that could be used to replace the fossils fuels in the near future. In this paper, simulation of engine will be done using AVL Boost to study the effects of six parameters on natural gas engine's performance and emission characteristics. Optimization will then be done to further improve the engine conditions.