To get a high-flux and high-uniformity spot in the target of solar simulator, the design and optimization of reflector are needed. Using non-coaxial ellipsoidal reflector to improve the quality of spot, the flux uniformity of spot is improved obviously. By using Monte-Carlo ray tracing method, a high flux concentrating solar simulator is designed. The target of 80 mm diameter can receive 10 kW radiative power on the second focal plane. The symmetry and uniformity of radiative spot are good, and the transfer efficiency of system from source to target is 23.81%. The average flux is 2 MW/m2 in the 80 mm diameter target and the flux can get 3.64 MW/m2 in the 50 mm diameter target which corresponds to a theoretical stagnation temperature of 2800 K. Non-coaxial ellipsoidal reflector is used to manufacture a solar simulator making up of supply control system, cooling system, xenon lamps and a condenser system. The focusing spot of solar simulator obtained in experiment test accords with the model spot by optical design simulation software TracePro.