According to Wick's theorem, the second order self-energycorrections of hadrons in the hot and dense nuclear matter arecalculated. Furthermore, the Feynman rules are summarized, and aneffective formulation on quantum hadrodynamics at finite temperaturesand densities is evaluated. As the strong couplings between nucleonsare considered, the self-consistency of this method is discussed inthe framework of relativistic mean-field approximation. Debyescreening masses of the scalar and vector mesons in the hot anddense nuclear matter are calculated with this method in therelativistic mean-field approximation. The results are differentfrom those of thermofield dynamics and Brown-Rho conjecture.Moreover, the effective masses of the photon and the nucleon in thehot and dense nuclear matter are discussed.