Lead-free　piezoelectric　powders,　K0.5Bi0.5TiO3　(KBT),　were　synthesized　by　sol-gel,　hydrothermal　and　sol-gel-hydrothermal　methods,　respectively.　The　structures　and　morphologies　of　the　powders　were　characterized　by　X-ray　diffraction　(XRD),　scanning　electron　microscopy　(SEM)　and　transmission　electron　microscopy　(TEM).　The　results　show　that　the　pure　perovskite　KBT　powders　can　be　obtained　by　all　three　methods;　however,　the　formation　mechanism　and　morphology　evolution　of　powders　prepared　by　various　processes　are　quite　different.　It　was　deduced　that　the　solid　diffusion　mechanism　was　applied　to　sol-gel　process.　Due　to　the　high-temperature　treatment　above　700　degrees　C,　the　KBT　powders　produced　by　sol-gel　method　had　large　size　with　serious　agglomeration.　The　cubically　shaped　nanopowders　were　prepared　by　hydrothermal　method,　which　belongs　to　dissolution-crystallization　mechanism.　The　in-situ　transformation　mechanism　was　applied　to　sol-gel-hydrothermal　process,　and　gel　clusters　played　a　crucial　role　in　the　formation　of　nanowire　morphology.