In this paper, the parametric sensitivities of a structure preserving a power system model are derived in the interest of effective model reduction. This parametric sensitivity analysis defines the sensitivity of a steady state point against the variation of a particular system parameter. The parametric sensitivities are derived here by studying the effects changes in a given parameter over the system natural modes of the variations on the small signal stability and the results obtained were confirmed. Also the correlations between different inherent modes resulting from small perturbation stability have been confirmed.