A numerical investigation was conducted to study the combustion characteristics in a five-point lean direct injection combustor. The influence of the pilot's swirl number to the combustion characteristics at both idle and takeoff conditions was carried out. The simulation results show that the radial dimension of the central recirculation zone without-reaction is lower than under-reaction at idle condition; but at takeoff condition, there're few distinctions on the structure of the central recirculation zone between the flow fields under-reaction and without-reaction. With the increasing of the pilot's swirl number, the radial dimension of the central recirculation zone increases. The temperature distributions of the center section are different because of the mutual interferences of the pilot and main stage. And with the increasing of the pilot's swirl number, the NOx emissions of the exit of the combustor increases.