In　this　work,　the　frequency　dependence　of　ferroelectric　and　electrocaloric　properties　in　barium　titanate-based　ceramics　was　studied　based　on　Maxwell　relations.　It　is　found　that　the　maximum　and　remnant　polarization　will　decrease　while　the　coercive　field　increases　a　lot　with　rising　frequency　from　0.1　to　10Hz,　indicating　that　polarization　rotation　and　domain　switching　become　difficult　at　high　frequencies.　The　electrocaloric　properties　show　the　different　frequency　dependence　at　different　phase　structures.　Isothermal　entropy　change　(Delta　S)　and　adiabatic　temperature　change　(Delta　T)　are　similar　around/above　Curie　temperature　(TC),　showing　tiny　frequency　dependence.　However,　Delta　S　and　Delta　T　display　the　obvious　frequency　dependence　below　TC,　especially　in　the　orthorhombic-tetragonal　phase-transition　region　with　a　stable　ferroelectric　phase,　and　this　frequency　dependence　becomes　more　obvious　under　a　low-electric　field.　It　is　also　found　that　increasing　the　frequency　can　weaken　the　electric　field　dependence　of　electrocaloric　strength.　This　work　gives　a　general　profile　of　frequency　dependence　for　electrocaloric　properties　in　ferroelectric　ceramics.