The　direct　fraction　of　sun　irradiation　is　used　to　focus　on　Fresnel　lens　in　High　Concentrated　Photovoltaic　technology,　electric　energy　is　produced　through　photoelectric　inversion.　However,　because　of　many　factors　in　practice　like　the　low　tracking　accuracy　of　tracker,　structure　vibration　by　winds　and　atmospheric　scattering,　the　direct　normal　irradiation　to　the　Fresnel　lens　can　not　be　guaranteed.　To　solve　this　problem,　a　removable　secondary　mirror　whose　shape　was　a　reverse　cone　with　no　top　was　added　between　the　Fresnel　lens　and　solar　cells　to　increase　the　acceptance　angle　of　the　solar　module.　A　design　example　was　given,　and　analyzed　by　optical　simulation　with　the　software　of　Solidworks　and　Tracepro.　The　conclusion　indicates　the　removable　secondary　mirror　can　increase　the　acceptance　angle　and　improve　the　irradiance　uniformity　of　the　focus　spot.　©,　2014,　Chinese　Society　of　Astronautics.　All　right　reserved.