Based on Walecka model, the refativistic microscopic optical potentials (RMOP) for nu-cleon-nucleus are investigated in the improved local density approximation (ILDA). The RMOP in ILDA, which include the effect of interaction range, are obtained by folding RMOP in LDA with Gaussian form factors. The parameters in Gaussian form factors are adjusted to fit the empirical values of the volume integral and root mean squar radius of the optical potential for p-Ca. By analysing the elastic scattering of proton from nuclei, we get a better agreement of ILDA with experiment data than that of LDA.