In this study, a numerical mesoscale model, COAMPS, was utilized to simulate the life cycle of two hurricanes occurring in 1999, Dennis and Floyd. The verification against various observation including satellite and best analyses revealed that the model captured reasonalbly well the evolution of the storm based on the intensity and track. Furthermore, in order to explore the inner-core structure of mature hurricane, high spatial resolution scheme (3km) was used for two cases. The axisymmetric and asymmetric component analyses was employed to investigate the horizontall and verticall kinetic and thermodynamic structures. There were seven circulations revealed within mature hurricane, Main Inflow (MI), Lower-level Outflow (LO), Return Outflow (RO), Sloping Updraft (SU), Main Downdraft (MD), Main Outflow (MO) and Return Inflow (RI). These circulations played important role in the development of the storm. In addtion, at all altitude, the storm center tended to tilt left-ward and the convective activities have a favourable location to occur over the left- and front- part of the storm.