To　improve　high　speed　machining　quality,　a　connection　performance　evaluation　model　for　spindle/toolholder　system　was　built　by　using　contact　finite　element　method.　Contact　detection　of　all　Gaussian　integration　points　was　implemented　at　the　contact　elements.　Contact　state　was　determined　by　calculating　normal　distance　and　normal　contact　force　between　every　two　points　on　the　contact　surface;　friction　state　was　determined　by　calculating　tangential　contact　force.　The　determinations　of　inequality　were　introduced　into　variational　principle　of　nonlinearity　Finite　Element　Method　(FEM)　by　penalty　function,　and　the　updated　equations　were　solved　by　full　Newton-Raphson　method.　The　influences　of　broach　force　and　rotation　speed　were　calculated　and　compared　by　statistical　deformation　and　stress　analysis　of　contact　faces.