The　laser　pulse　modulation　instabilities　in　partially　stripped　plasma　were　discussed　based　on　the　phase　and　group　velocities　of　the　laser　pulse　and　the　two　processes　that　modulation　instabilities　excited.　The　excitation　condition　and　growth　rate　of　the　modulation　instability　were　obtained.　It　was　found　that　the　positive　chirp　and　competition　between　normal　and　abnormal　dispersions　play　important　roles　in　the　modulation　instability.　In　the　partially　stripped　plasma,　the　increased　positive　chirp　enhances　the　modulation　instability,　and　the　dispersion　competition　reduces　it.