The　interface　incompatibility　between　organic　polymer　and　inorganic　ceramic　filler　is　a　common　phenomenon　in　polymer-based　dielectric　composites.　In　this　paper,　the　Ar/CF4　plasma　is　used　to　modify　the　CaTiO3　particles,　which　improved　the　dispersion　of　CaTiO3　and　its　compatibility　with　polytetrafluoroethylene　(PTFE).　The　findings　demonstrate　that　growing　argon　(Ar)　flow　rate　was　beneficial　to　enhance　discharge　and　increase　fluorinated　graft　content.　The　modified　CaTiO3/PTFE　is　uniformly　distributed　and　has　no　serious　agglomeration　phenomenon,　which　effectively　improves　its　dielectric　characteristics.　Modified　CaTiO3/PTFE　composite　with　5　wt.%　CaTiO3　has　a　dielectric　constant　of　2.32　whilst　the　dielectric　loss　reaches　2.8　×　10-3　at　around　10　GHz.　©　Published　under　licence　by　IOP　Publishing　Ltd.