Co-gasification of coal and biomass is the new sensation in energy production as it provides two benefits: coal for high density of energy and biomass for a clean and renewable energy source. The advantages of the gasification process are many. The producer gas from gasification is multipurpose and can be used for producing electricity in gas engines and turbines, for Fischer-Tropsch synthesis of liquid fuel and even for producing gaseous products such as synthetic natural gas like the SNG. A variety of mixtures and compositions of coal and wood provides great flexibility that best fits the desired product. In this study a basic gasification model is developed by Aspen plus Simulation Software based on the report of low rank coal to electricity IGCC cases. Simulation of different coal and wood (Radiata pine) co-gasification process was performed by applying the basic model. Entrained flow Siemens water quenched gasifier is proposed for the basic model for simulating gasification of different ratio of fuel blend. 40% lignite and 60% radiata pine, 70% lignite and 30% radiata pine, 80% lignite and 20% radiate pine, and finally 100 % lignite used for the co- gasification model. Carbon conversion and cold gas efficiency are also calculated to determine energy efficiency. Sensitivity analysis was also performed according to pressures and oxygen/ fuel blend ratios. A Low oxygen amount is required for co-gasification compared to 100% lignite coal. And there is no big pressure effect on the gas compositions production. From the result it clearly show that the 80% lignite coal and 20% radiata pine produces the highest amount of syngas compared to other fuel blend ratios. Biomass is carbon neutral and it is proved as it shows that the effective amount of CO2 is very low. On the other side H2S and NH3 mole flow increased after increasing the coal amount in the blend ratio. The final output of the syngas H2/ CO also indicated a good ratio for 80% lignite and 20% radiate pine.