In　this　paper,　we　report　the　single　mode　operation　of　PC-VCSEL.　The　PC-　VCSEL　is　similar　to　standard　VCSEL　except　that　it　has　photonic　crystal　defined　by　holes　in　the　top　distributed　Bragg　reflector.　The　two-dimensional　photonic　crystal　(2-D　PhC)　structure　is　applied　to　lateral　mode　control　of　VCSEL.　The　optical　confinement　in　VCSEL　is　realized　by　adding　air-holes　in　the　top　(DBR).　The　holes　are　arranged　periodically　such　that　they　form　a　triangular　or　square　symmetric　pattern.　Light　emitting　aperture　is　formed　by　removing　some　air　holes　centered　at　photonic　crystal　pattern.　By　adjusting　the　photonic　crystal　parameters　and　air-holes　depth,　a　variety　of　optical　mode　characteristic　can　be　achieved.　The　characteristics　of　lasing　lateral　modes　in　PhC-VCSEL　were　analyzed　by　etching　depth　related　effective　index　method.　The　contribution　of　PhC　parameters　such　as　lattice　constant　a,　holes　diameter　d　and　uniform　material　index　n　to　lateral　mode　characteristic　is　investigated　systematically.　Then　two　dimensional　PhC　was　fabricated　using　electron　beam　lithography　(EBL)　and　inductive　coupled　plasma　reactive　ion　etching　(ICP-RIE)　on　the　surface　of　the　VCSEL＇s　top　DBR.　A　single-fundamental-mode　output　power　bigger　than　1mW,　threshold　current　below　5　mA,　Full　Width　Half　Maximum　(FWHM)　of　lasing　spectrum　is　less　than　0.06　nm　and　over　30dB　SMSR　PhC-VCSEL　was　obtained.　The　lateral　mode　characteristics　affected　by　different　current　injection　was　also　considered.