Process capability indices, Cp, Cpk, Cpm, and Cpmk can be used to evaluate single quality characteristic. Recently, many of the multivariate capability indices have been developed to assess a part which has several correlated quality characteristics. Principal component analysis(PCA) can transform the correlated quality characteristics into the newly independent factors. The existing formula calculates the Mutivariate Process Capability Index using the geometrical average. But, the result value notably differs from the number of principle component. In this paper, We proposed a new multivariate capability using PCA & RSS.