A new multi- plane mirrors linear combination solar concentrator is proposed for concentrating photovoltaic system. Based on the new concentrator, the geometric concentrator parameters that affect the optical performance are studied using analytic geometry method. The concepts of the minimum design spacing and cosine efficiency are proposed. The interactional condition between focal length and different sizes of sub-mirror, as well as between focal length and different numbers of sub-mirror investigated, and the optimization of the minimum design spacing and cosine efficiency are given. A model developed by TracePro software is used to obtain the flux distribution of the focal plane at different simulation parameters. An experimental prototype concentrator with 450× suns is fabricated and preliminary tested, the operation shows that the effect is obvious and the expected results is arrived. The simulation results can present a useful reference for design and optimization of the solar concentrator.