Particle image velocimetry (PIV) method,which has been widely applied in flow field testing in recent years,is a flow measurement technique using laser imaging tec hnology.XFD floatation machines are most frequently used in floatation experiments.Research on their characteristics of flow fields can provide basic data for floatation-machine de sign and promote design level of floatation machine.In this paper,related experi ments have been performed on investigating flow field in XFD-1.5L floatation ma chine to reveal its characteristics by PIV method.When agitation speed of the floatation machine i s set at 1000r/min,three planes (10-10,0-20and 30-30) in the sti rring tank are illuminated by laser and studied.As a result,the main characteristics can be described as follows:t he fluid circuits from stirring tank to the chute;the main cell consists of three zones,which ar e the zone between Y=0~25mm mainly with horizontal circulating flow,the zo ne between Y=25~120mm mainly with rising flow and the zone between Y=120~145mm mainly wit h horizontal flow moving towards the chute,corresponding to stirring zone,separating zone and froth zone desc ribed by floatation theory,respectively.The results suggest that the design of t he floatation machine is rational and can facilitate mineral separation.