To　investigate　the　relationship　of　surface　electromyogram　(sEMG)　and　handgrip　force,　a　measurement　system　was　developed.　Ten　healthy　subjects　were　required　to　perform　a　series　of　static　contraction　trials　by　maintaining　the　force　level　with　maximal　voluntary　contraction　(MVC),　75%MVC,　50%MVC　and　25%MVC　respectively.　Then　they　sustained　MVC　as　long　as　possible　until　fatigue.　The　handgrip　force　and　sEMG　on　the　forearm　muscles　were　recorded.　Root　mean　square　(RMS),　mean　power　frequency　(MPF)　and　median　frequency　(MF)　of　the　sEMG　were　calculated　with　LabVIEW.　The　results　show　that　RMS　increased　with　force　level　during　voluntary　contraction,　while　MPF　and　MF　shift　to　lower　frequency　during　fatigue　condition.　These　findings　suggested　that　the　designed　system　can　be　used　to　study　forearm　function.