Placenta　accreta　is　one　of　the　most　serious　complications　of　obstetrics.　As　a　gold　standard,　the　postnatal　pathological　examination　has　hysteresis　and　limitation.　In　this　paper,　the　multi-feature　associations　of　medical　history　information　and　color　Doppler　ultrasound　data　are　used　as　observation　sequences　and　the　postpartum　pathological　results　are　used　as　hidden　state　sequences.　The　prenatal　prediction　method　of　placenta　accreta　based　on　hidden　Markov　model　is　proposed.　The　algorithm　of　Gini　is　used　to　extract　the　disease　factors.　Then,　the　hidden　Markov　model　is　built　by　the　set　of　factors.　Through　the　observation　and　hidden　sequences,　the　prenatal　prediction　of　placenta　accreta　is　accomplished　using　Baum-Welch　and　Viterbi　algorithms.　The　experimental　results　show　that　the　proposed　method　achieves　better　diagnostic　accuracy,　sensitivity　and　specificity.　©　2017,　Science　Press.　All　right　reserved.