Combustor development for industrial gas turbine requires extensive experience and massive resources. Due to a recent development of computing power, computational fluid dynamics (CFD) became one of main analysis tools for combustion research. In this paper, both experiment and numerical studies of a lean premixed combustor with an axial-type swirler were conducted. Flow field measurement using PIV was compared with CFD result with various turbulent models. Large eddy simulation (LES) with dynamic Smagorinsky model showed the highest accuracy in recirculation zone prediction. Flamelet progress variable (FPV) method was used to model partially premixed combustion. Reaction zones were visualized by OH concentration from experiment and LES calculation, and they showed good agreement. In addition to the flame shape, complex flow physics inside a lean premixed combustor was observed in LES result. Numerical approach described in this paper will be applied to design Samsung Techwin"s original combustors.