Abstract: In this paper, numerical simulation of skew stators with inlet chamber of ultra supercritical steam turbines is carried out through CFX. By analyzing the inner flow field of skew stators, losses and benefits from skew stators can be obtained, which provides references to future design of skew stators and improves the through-flow design. Based on the distribution of the flow angle at the inlet, the blade surface pressure at different circumferential positions, and the velocity vectors and static pressure contours at 50% span, it could be concluded that the circumferential asymmetry due to inlet chamber would affect the flow in downstream blade rows, causing deviation in the working state of the steam turbine, eventually undermining the machine. However, with a row of skew stators installed, the circumferential asymmetry condition is improved significantly, and the flow in the downstream blade rows becomes much more uniform, which is seen to be helpful for the operation of the turbine and the protection of rotors.