Because of the large divergence angle and small test caliber, the solar simulator is not suitable for the test of photovoltaic concentration system. In order to make up this weakness, an indoor concentration test system with a large caliber and a high parallelism is designed. A new concentration test method——discrete spectral local measurement method——is proposed. Firstly, two-stage Fresnel concentration system is chosen as a test object and monochromatic light local measurement method is used to test its concentration efficiency. Then the average concentration efficiency is calculated according to the weight and concentration efficiency of monochromatic light. Finally, the experimental results are compared with the simulated results. The simulated concentration efficiency is 88.623%, and the measured concentration efficiency is 85.45%, with the difference of 3.173%. The transmittance and the uniformity of concentration spot are quite close. The difference of concentration efficiency mainly come from manufacturing error and measuring error. The scientificity and feasibility of the indoor concentration test system are confirmed through the experimental data analysis. The light divergence angle of indoor concentration test system is 0.267°, which can match sunlight divergence angle, and its 145 mm caliber can test the performance of concentration system with the large caliber. Indoor concentration test system with simple structure and low cost will have broad application prospects in solar-energy concentration field.