Gasification is an efficient method of producing clean synthetic gas which can be used as fuel for electric generation and chemical for industries use. Gasification process simulation of coal inside a generic two-stage entrained flow gasifier to produce syngas was undertaken. Numerical simulation of the oxygen blown coal gasification process inside a two-stage entrained coal gasifier is studied with the commercial CFD solver ANSYS FLUENT. The purpose of this study is to use CFD simulation to improve understanding of the gasification processes in the state of art two-stage entrained flow coal gasifier. Three dimensions, Navier-Stokes equations and species transport equations are solved with the eddy-breakup reaction model to predict gasification processes. The influences of coal/water slurry concentration and O2/coal ratio on the gasification process are investigated. The coal-to-water slurry concentrations in this study were 0.74 and O2/coal ratio is 0.91. Coal slurry fed the predicted concentration of 47.7% and CO was 25% with higher syngas heating value of 27.65 MJ/kg. The flow behavior in the gasifier, especially the single fuel injection design on the second stage, is examined and validated against available data in the literature.