In this research we described the effective Hamiltonian theory and applied this theory to the calculation of current-current (Q1,2) and QCD penguin (Q3,…,6) c quark decay rates. We calculated the decay rates of semileptonic and hadronic of charm quark in the effective Hamiltonian theory. We investigated the decay rates of D meson decays according to Spectator Quark Model (SQM) for the calculati...