Depolarization　mechanism　and　compensation　scheme　of　radially　polarized　beams　under　non-uniform　pumping　were　investigated.　Theoretical　analysis　shows　that,　for　the　non-uniform　pumping　status,　the　thermal　induced　shear　birefringence　caused　by　the　thermally　induced　shear　stress　within　the　cross-section　of　the　isotropic　crystal　is　the　main　reason　for　the　depolarization　of　the　radially　polarized　beams.　Related　experiments　were　designed　to　evaluate　the　depolarization　of　the　radially　polarized　beams　under　non-uniform　pumping　conditions　by　using　two　methods　of　thin-film　polarizer　(TFP)　measurement　and　purity　measurement,　in　which　the　TFP　measurement　method　was　used　to　detect　the　overall　depolarization　of　radially　polarized　beams　and　the　purity　measurement　method　was　used　to　detect　local　depolarization　of　radially　polarized　beams.　With　a　peak　pump　power　of　1.1　kW,　the　depolarization　measured　by　the　two　evaluation　methods　was　2.34%　and　2.53%,　respectively.　Based　on　the　theoretical　analysis　and　evaluation　results,　a　combination　of　phase　modulation　and　spatial　mode　matching　was　considered　in　the　design　of　the　depolarization　compensation　scheme,　which　improved　the　depolarization　of　the　radially　polarized　beams　by　59%.　Meanwhile,　a　picosecond　radially　polarized　beam　with　a　pulse　energy　of　19.36　mJ,　a　purity　of　90.13%,　and　a　beam　quality　M2　factor　of　3.8　was　achieved.　Copyright　©2021　Infrared　and　Laser　Engineering.　All　rights　reserved.