To solve the problem of low irradiance caused by the low energy utilization rate of an existing solar simulator， a Compound Parabolic Concentrator （CPC） based on the basic imaging principle of the solar simulator was proposed to improve the concentrating system of the simulator. The condensing mechanism of the CPC and a traditional condenser was analyzed， and the parameter design method of the CPC was derived based on the edge-ray principle. Using the LightTools software combined with a nested body light source and the CPC to build a condenser model， the ideal maximum receiving angle of the CPC was analyzed. A comparison model between the ellipsoidal condenser and the combined condenser system was established to verify the theoretical analysis. The optimal intercept ratio was obtained through an intercept analysis to optimize the initial structure and to determine the final structure of the CPC. Results show that the energy utilization rate of xenon lamps used in the CPC is as high as 94.86%. Furthermore， the irradiance of the entire solar simulator can be greatly improved. The findings of this study present a reference for designing highly energy efficient and high-irradiance solar simulators.