Performance　analysis　and　kinematic　design　of　the　3-PUU　pure　translational　parallel　mechanism　with　vertical　guideways　are　investigated.　Two　novel　performance　indices,　the　critical　slider　stroke　and　the　main　section　area　of　workspace,　are　defined;　The　expressions　of　two　other　indices,　i.e.　the　global　dexterity　and　global　force　transfer　ratio　are　revised　based　on　the　main　section　of　workspace.　Using　these　indices,　performance　changes　versus　the　varieties　of　dimensional　parameters　of　mechanism　are　investigated　and　the　graphic　descriptions　of　change　tendencies　of　the　performance　indices　are　illustrated.　By　means　of　these　obtained　graphic　descriptions,　kinematic　parameters　for　the　3-PUU　pure　translational　parallel　mechanism　with　better　characteristics　can　be　directly　acquired.