With　the　rapid　development　of　information　technology,　a　wavelength-tunable　vertical　cavity　surface　emitting　laser　(VCSEL)　is　urgently　needed　as　an　optical　signal　source　in　dense　wavelength　division　multiplexing　(DWDM).　Liquid　crystal　tunable　VCSEL　realized　by　utilizing　the　birefringence　characteristics　of　liquid　crystal　has　the　advantages　of　stable　polarization,　high　reliability,　continuous　wavelength　tuning.　In　this　paper,　a　liquid　crystal　tunable　VCSEL　structure　based　on　intracavity　sub　wavelength　grating　is　designed,　and　the　influence　of　liquid　crystal　layer　and　sub　wavelength　grating　on　the　wavelength　tuning　characteristics　of　VCSEL　are　analyzed　and　studied　in　depth.　The　results　show　that　the　thickness　of　the　liquid　crystal　layer　in　the　tunable　VCSEL　structure　not　only　affects　the　wavelength　tuning　range,　but　also　determines　the　mode　hopping　in　the　tuning　process.　In　addition,　an　effective　refractive　index　antireflection　layer　is　formed　by　designing　the　subwavelength　grating　structure,　and　the　refractive　index　difference　between　the　liquid　crystal　layer　and　the　semiconductor　layer　is　optimized　to　further　improve　the　wavelength　tuning　range　and　tuning　efficiency.　When　the　center　wavelength　is　980　nm,　the　tuning　range　is　increased　by　42%,　reaching　41　nm,　and　the　wavelength　tuning　efficiency　is　increased　by　41%.　It　provides　a　new　method　of　designing　the　VCSEL　laser　with　high　beam　quality　and　continuous　wavelength　tuning.