Abstract: Particle image velocimetry(PIV) was applied to a multifunctional rotating facility,the velocity distributions in the rotating cavity with a radial inflow of fluid had been measured in different working conditions.The experimental facility,experimental method and error analysis were introduced.The instantaneous and ensemble-average velocity fields in the rotating cavity had been discussed in this paper.And the results show PIV can be used to analyze the velocity field in a complex rotating cavity and the influence of non-dimensional mass flow-rate and rotating Reynolds number.At the same time,the light reflection control and the symmetrical and steady dispersion of tracer particles are the key factors of the PIV measurement.