In order to obtain excellent gas jet from laser’s nozzle, a combinatorial supersonic laser jet cutting nozzle is designed. The control equation for computational fluid dynamics (CFD) is also derived, where standard k-ε model is used for onflow. Using triangle unstructured grid for computing, applying finite volume algorithm to discretizing the control equation, the equation is solved by coupling solver. Velocity and pressure coupling problem is solved by applying SIMPLEC algorithm, and further more the jet field analysis is fulfilled. The analysis indicate that the optimum pressure-inlet is its designed pressure (7×105 Pa), under which the jet field performs best and so it can be sufficiently applied to cut thick workpiece with high velocity. Comparing the results of CFD analysis with that of image lab obtained, it is found that the two results have a quite good consistency. Thus, the CFD analyzing method is proved practical.