Indonesia has a fairly large biomass commodity. In order to produce energy that can be used by society, qualified skills and technology are needed. Gasification is one of the processes to convert biomass into combustible gasses using a gasifier. A lot of studies has been conducted to get best quality of syngas which contain highest energy. In this study, operating standard of the gasifier are identified to get the best gas quality. By using numerical simulation analysis, the research will be easier. Cheaper, and lower risk. The result for operating standard of a gasifier with a height of 60 cm and a diameter of 25 cm is obtained, the primary flow rate is 2.83 m3/h and for fuel consumption rate is 4.05 kg/h. From those parameters, the value of HHV from producer gas is 5.79 MJ/Nm3.