The　effect　of　CO2　laser　irradiation　on　the　dielectric　properties　of　PZT-4　ceramic　is　investigated.　After　laser　irradiation,　dielectric　permittivity　and　dielectric　loss　of　the　ceramic　decrease　5%　and　60%,　respectively,　and　the　coercivity　increases.　The　mechanism　of　the　changes　are　analysed　by　Raman　scattering,　scanning　electron　microscope　(SEM),　X-ray　diffraction　(XRD)　and　the　annealing　process.　It　is　shown　that　the　microstructure　changes　of　the　irradiated　sample　mainly　account　for　the　dielectric　properties.　The　CO2　laser　irradiation　could　induce　the　tension　stress,　leading　to　the　larger　lattice　parameter　and　the　deviation　of　B　site　ion　from　the　center　of　oxygen　octahedron.　The　distortion　of　the　oxygen　octahedron　results　in　the　less　activation　of　electric　domains.　Therefore,　the　polarization　switching　of　the　electric　domains　become　more　difficult,　exhibiting　the　properties　of　＇hard＇.　This　suggests　that　the　laser　irradiation　may　offer　a　new　approach　for　the　fabrication　of　lead　zirconate　titanate　(PZT)　based　＇hard　martial＇　in　several　seconds　without　any　ions　addition.