Based on the mode field theory of passive fiber and rate equation of active fiber, the calculative method of effective mode area and extraction efficiency of fundamental mode for large mode area fibers with arbitrary refractive-index profile and dopant distribution of is presented. The performance of various designs for the core refractive-index and dopant distributions of large-mode-area fibers are numerically simulated and compared. The analysis shows that the hybrid profile fiber exhibits better overall performance than other traditional fibers in the design of large-mode-area fibers with core diameter of hundreds of microns.