OBJECTIVE:　To　investigate　the　effect　of　force　level　and　fatigue　on　brain　activity　during　handgrip　tasks.　METHODS:　Electroencephalography　(EEG)　signals　were　recorded　from　eleven　healthy　male　subjects　when　they　performed　25%,　50%　and　75%　maximal　voluntary　contraction　(MVC),　and　were　in　fatigue　state.　EEG　powers　in　different　handgrip　tasks　were　analyzed　in　the　frequency　domain　and　time　domain　respectively.　RESULTS:　The　EEG　power　at　25%　MVC　was　significantly　lower　than　that　at　75%　MVC　in　gamma　band　(p　＜　0.05)　for　electrode　C3,　C4,　Cz,　Pz　and　Fz.　EEG　power　at　25%　MVC　was　also　significantly　lower　than　that　at　75%　MVC　in　beta　band　(p　＜　0.05)　for　electrode　C3.　However,　the　handgrip　force　level　and　fatigue　did　not　affect　the　EEG　powers　for　the　other　frequencies　and　electrodes　(p　＞　0.05).　CONCLUSION:　The　results　suggest　that　handgrip　force　level　may　modulate　the　brain　activity　in　certain　frequency　bands　and　cortical　regions.　EEG　power　is　a　useful　tool　to　characterize　the　motor　state.