Gas-lift　pump　in　liquid　metal　cooling　fast　reactor　(LMFR)　is　an　innovative　conceptual　design　to　enhance　the　natural　circulation　ability　of　reactor　core.　The　two　phase　flow　characteristics　of　gas　liquid　metal　make　significant　improvement　of　the　natural　circulation　capacity　and　reactor　safety.　It　is　important　to　study　bubble　flow　in　liquid　metal.　In　present　study,　the　rising　behaviors　of　a　single　nitrogen　bubble　in　5　kinds　of　common　stagnant　liquid　metals　(lead　bismuth　alloy　(LBE),　liquid　kalium　(K),　sodium　(Na),　potassium　sodium　alloy　(Na-K)　and　lithium　lead　alloy　(Li-Pb))　and　in　flowing　lead　bismuth　alloy　have　been　numerically　simulated　using　two-dimensional　moving　particle　semi-implicit　(MPS)　method.　The　whole　bubble　rising　process　in　liquid　was　captured.　The　bubble　shape,　rising　velocity　and　aspect　ratio　during　rising　process　of　single　nitrogen　bubble　were　studied.　The　computational　results　show　that,　in　the　stagnant　liquid　metals,　the　bubble　rising　shape　can　be　described　by　the　Grace＇s　diagram,　the　terminal　velocity　is　not　beyond　0.3　m/s,　the　terminal　aspect　ratio　is　between　0.5　and　0.6.　In　the　flowing　lead　bismuth　alloy,　as　the　liquid　velocity　increases,　both　the　bubble　aspect　ratio　and　terminal　velocity　increase　as　well.　This　work　is　the　fundamental　research　of　two　phase　flow　and　will　be　important　to　the　study　of　the　natural　circulation　capability　of　Accelerator　Driven　System　(ADS)　by　using　gas-lift　pump.　(C)　2012　Elsevier　Ltd.　All　rights　reserved.