Experimental and theoretical studies are conducted on the effect of cyclones inlet shape on particle collection performance. Due to the centrifugal effect on incoming particles, the collection efficiency of a cyclone with curved inlet is higher than that with a straight inlet. It is found that the collection efficiency for both types increases with increasing cyclone inlet velocity, and experimental data agree with calculated results. From numerical simulation, it is also found that some of the particles are deposited in the inlet region of the dust box.