Ablackphosphorus(BP)saturableabsorber(SA)solutionwithdifferentconcentrations(1.0and0.5mg/ml)isfabricatedwiththeliquid-phaseexfoliationmethod.ByusingtheBP-SA,acompactdiode-pumpedpassivelyQ-switchedNd:YV04laserisdemonstrated.OnereflectingBragggratingsisusedastheoutputcouplerformodeselection.ByinsertingthoseBP-SAsolutionsinthelasercavity,themaximumsinglelongitudemode,Q-switchedoutputpowersof126mWat692.5kHzand149mWat630.3kHzareachievedatthepumppowerof8.0W,correspondingtothepulsedurationsof144nsand196ns,respectively.Moreover,longitudinal-modecharacteristicsofQ-switchedoutputlaserindifferentopticalcavitylengthsbasedontwo-kindBP-SAsolutionconcentrationsareinvestigated.OurresultsshowthatBP-SAcouldalsobedevelopedasaneffectiveSAfortheQ-switched,singlelongitudinalmodepulselaser.