Abstract: A high speed camera is used to photograph the motion process of particles through turbine cascade.The effects of particle size and initial position on the particle trajectories and velocities are analyzed.The particle trajectories and velocities are also computed with the Lagrangian method under conditions of flow with and without boundary layer.Comparison between computational and experimental results shows that it is necessary to consider the effect of the boundary layer for the smaller particles,but it is unnecessary for the larger particles when the Lagrangian method is used to compute the motion behaviours of particles.