Abstract:As a steam turbine especially a super-critical pressure steam turbine operates sliding from rated condition, some improper schemes of steam intake will produce big imbalance force in governing stage, furthermore, induce failure involved eccentricity and overheat of bearing bush nearing the governing stage, weaken the safety of turbine. Simply considering the reduction of the steam distribution scheme of the unbalanced steam flow,which will result in the reduction of the regulation level efficiency and the overall efficiency of the turbine. So how to deal with the problem of the safety against the efficiency of the turbine is a key point as the steam distribution modes being decided. This paper expounds the influence of unbalanced steam turbine generating mechanism of steam force and its cause, for a certain type of 600MW super critical steam turbine in 30%, 80% and 90% load points, set up different steam distribution scheme on steam flow imbalance of power and efficiency of governing stage of detailed calculation, the analysis scheme comparison from two angles of economy and security, according to the results of calculation and analysis is proposed to reduce the unbalanced steam force and improve the efficiency of governing stage of the collaborative optimization scheme.