Only　the　direct　fraction　of　the　sun　irradiation　can　be　used　in　high　concentration　photovoltaic　technology.　There　are　a　number　of　deficiencies　like　the　low　tracking　accuracy　of　tracker,　structure　vibration　by　winds　and　atmospheric　scattering　in　practice,　which　leads　to　non　vertical　incident　irradiation　to　the　Fresnel　lens.　To　slove　the　problem　of　non　vertical　incident　irradiation　to　the　Fresnel　lens,　a　removable　secondary　mirror　whose　shape　is　a　reverse　cone　with　no　top　is　addedbetween　the　Fresnel　lens　and　solar　cells　in　this　paper,　to　increase　the　acceptance　angle　of　the　solar　module.　A　design　example　is　given,　and　is　analyzed　by　optical　simulation　with　the　software　of　Solidworks　and　Tracepro.　The　conclusion　is　drawn　that　the　removable　secondary　mirror　increase　the　acceptance　angle　and　improve　the　irradiance　uniformity　of　the　focus　spot.