This paper is devoted to reconsider the one-loop oblique corrections arising from the scalar superpartners in the MSSM, that is, the squarks, the sleptons, and the scalars in Higgs sector. We explicitly present the complete one-loop forms of self-energy corrections to the gauge bosons of SM electroweak gauge groups, as well as their descendants the S , T , and U parameters, which can be directly applied to constrain the parameter space of the MSSM. Our results about one-loop self energies are found to agree with Drees et al. (1992) and Pierce et al. (1997). Nevertheless, the S , T , and U parameters are not in agreement with Dobado et al. (1999).