For　the　problem　of　the　stress　distribution　in　cylinder　upsetting　process,　the　comparison　between　numerical　simulation　results　and　the　results　calculated　by　means　of　block　method　were　analyzed,　and　the　stress　distribution　and　its　changing　characteristic　in　different　positions　of　the　blank　were　observed,　the　influence　of　the　friction　coefficient　on　the　limit　height-diameter　ratio　was　investigated.　The　results　show　that　under　the　condition　of　friction,　when　upsetting　the　cylinder　with　high　height-diameter　ratio,tensile　stresses　in　radial　and　tangential　direction　are　generated　on　the　upper　and　the　lower　face　of　the　blank,and　the　tensile　stresses　in　two　directions　gradually　decrease　with　the　increase　of　reduction　and　eventually　turn　into　compressive　stress;　axial　compressive　stress　in　bulging　area　decreases　with　the　increase　of　reduction,　the　radial　stress　is　close　to　0　MPa,　and　loop　tensile　stress　increases　with　the　increase　of　reduction;　when　the　height-diameter　ratio　is　less　than　0.6,　tensile　stresses　in　radial　and　tangential　direction　are　not　generated　on　the　upper　and　the　lower　face　of　the　blank,　and　the　limit　height-diameter　ratio　has　nothing　to　do　with　the　coefficient　of　friction.　©　2017,　Editorial　Board　of　Journal　of　Plasticity　Engineering.　All　right　reserved.