Abstract: At present, the large demand and wide use of stable isotopes are greatly stimulating development on separation technologies with gas centrifuge. Adopting the unified expressions of the value function and the separation power, this paper derived the unified expression of the separation power that is described with the overall separation factor, the feed, the cut and the concentration of the feed. No restrictions were placed onto the parameters above in the derivation, thus this expression is more widely applicable. In the case of variation of the overall separation factor and the cut, the effect of the various factors on the separation power is analyzed.