The　research　and　development　of　the　Pinyin-to-Chinese-Character　conversion　is　the　core　technique　of　Chinese　Input　system,　Chinese　speech　recognition　and　Chinese　information　processing.　First,　the　state-of-the-art　of　Pinyin-to-Chinese-Character　conversion　is　briefly　dis　cussed,　and　its　principles　and　shortcomings　are　analyzed.　Then　the　conversion　approach　based　on　hybrid　word　lattice　is　proposed.　The　implementation　of　the　main　architecture　is　studied.　The　re　lated　problems　with　hybrid　language　model　and　the　algorithms　to　solve　the　word　lattice　are　inves　tigated.　Finally,　the　automatic　prediction　algorithm　and　the　machine　learning　technology　used　in　Chinese　intelligent　input　systems　are　discussed.　A　prototype　system　realized　based　on　the　pro　posed　approach　is　presented,　and　compared　with　the　MS　Pinyin　input　system　in　Windows　XP.　The　experimental　results　show　that　the　correct　conversion　rate　from　Pinyin　to　Chinese　characters　is　significantly　improved.