The GFS (Global Forecasting System) reanalysis and JMA (Japan Meteorological Agency) reanalysis data are applied as the initial conditions for the simulation of the super Typhoon Saomai in 2006 respectively in this study. Based on the WRF (Weather Research and Forecasting) Model, numerical simulations were conducted to analyze the influence of different initial conditions on the internal structure and movement path for Saomai. The results show: For the forecasts of the 500 hPa geopotential field and the composite field (such as water vapor and temperature) of 850 hPa, GFS and JMA data are able to well grasp the overall flow field situation. JMA data are superior to GFS data for simulating fields such as the wind speed (700 hPa and nearsurface), precipitation, radar reflectivity, minimum sea level pressure, and maximum wind speed. For the typhoon track forecast, JMA data in the first 15 hours are better than GFS data, but after 15 hours, both forecasting fields have a significant deviation.