Abstract
The transit, i.e. the flux-drop of a star due to the passing of a planet, has recently become one of the most popular methods in the search of extra-solar planets, and those confirmed cases show that the limb-darkening effect is important and cannot be ignored. We here develop a method to do the theoretical modeling of the transit light curves when the limb-darkening is included. Through our method, the observational data of a few planetary systems is used to determine the physical and orbital parameters. In addition to the best fitting parameters of planetary systems, the regions of the parameter space at different confidence levels will be presented. Finally, the effects of additional data of the host star's radial velocities are also investigated.