In this research we describe effective Hamiltonian theory and apply this theory to the calculation of current-current $Q_{12}$ and QCD penguin $Q_{3...6}$ decay rates We calculate the decay rates of semileptonic and hadronic of charm quark in effective Hamiltonian theory. We investigate the decay rates of D meson decays according to Spectator Quark Model(SQM) for the calculation of D meson decays. We obtain the total decay rates of semileptonic and hadronic of charm quark in effective Hamiltonian according to colour Favoured (C-F) and colour Suppressed (C-S), and then to added amplitude of processes colour Favoured and colour Suppressed (F-S) and obtain the decay rates of them.