Based　on　the　blood　theology　and　hydrokinetics　theory,　Casson　Equation　concerning　to　the　blood　flow　in　the　uniform　vessel　is　founded.　Combining　with　the　physiological　performance　parameters,　the　relationship　between　initial　blood　velocity　with　block　of　the　thrombus　and　the　maximal　velocity,　pressure　after　the　block　is　analyzed.　It　is　shown　that　the　higher　the　initial　velocity,　the　higher　the　maximal　velocity　and　pressure　will　be　after　the　block.　Furthermore,　a　series　of　＇locations　apt　to　thrombus＇　will　appear　in　the　vessel　behind　the　thrombus,　and　the　harm　to　the　health　is　predicted　in　this　paper.