This paper focuses on the investigation of the blade deformation and tip clearance effects of a high-flow-coefficient centrifugal compressor. Blade deformation caused by the pressure load and centrifugal load under operating condition is considered by fluid/solid interaction method to simulate the stage performance accurately. Hence the numerical results are in good agreement with the experimental data. The blade deformation is then analyzed in detail. Also, the effect of the size of tip clearance is studied by evaluating the performance with five various gaps. The result shows that the increment of the tip clearance from 0 to 2.0 mm leads to a 5.14% peak efficiency decline. However, increasing tip gap contributes to enlarge the stable operating range in terms of stall margin and choke margin.