According　to　Wick＇s　theorem,　the　second　order　self-energy　corrections　of　hadrons　in　the　hot　and　dense　nuclear　matter　are　calculated.　Furthermore,　the　Feynman　rules　are　summarized,　and　an　effective　formulation　on　quantum　hadrodynamics　at　finite　temperatures　and　densities　is　evaluated.　As　the　strong　couplings　between　nucleons　are　considered,　the　self-consistency　of　this　method　is　discussed　in　the　framework　of　relativistic　mean-field　approximation.　Debye　screening　masses　of　the　scalar　and　vector　mesons　in　the　hot　and　dense　nuclear　matter　are　calculated　with　this　method　in　the　relativistic　mean-field　approximation.　The　results　are　different　from　those　of　thermofield　dynamics　and　Brown-Rho　conjecture.　Moreover,　the　effective　masses　of　the　photon　and　the　nucleon　in　the　hot　and　dense　nuclear　matter　are　discussed.