| The properties of 0±,1±D mesons and 0++scalar glueball are investigated by using varies QCD sum rules in this thesis.In the first work of this thesis, we calculate the masses of 0±,1±D mesons and their couplings to the corresponding currents by using Gaussian sum rules. The forms of the two-point function of D meson current obtained by operator product expansion in heavy-quark effective theory and in full QCD are used. The corresponding Gaussian sum rules for the D mesons are obtained by means of Borel transformation. Based on it, and using the standard QCD input parameters, the masses and the coupling constants of D mesons are then predicted, the results are in good accordance with experimental data. Especially, the mass of DsO+(2317) meson has been obtained first time in full QCD with Gaussian sum rule to be m Ds(2317)= 2.32±0.13 GeV, which is consistent with experimental data.Our second work is devoted to calculate the mass, width and coupling constant of 0++ scalar glueball in both the finite-width Laplace sum rules and the finite-width Gaussian sum rules. In the framework of a semi-classical expansion for quantum chro-modynamics in the instanton liquid background, the correlation function of the 0++ scalar glueball current is given. Besides the pure classical and quantum contributions, the contributions arising from the interactions between the classical instanton fields and quantum gluons are taken into account as well. Instead of the usual zero-width approximation for the resonance, the Breit-Wigner form for the spectral function of the finite-width resonance is adopted. The family of the Laplace sum rules and Gaussian sum rules for the 0++ scalar glueball are derived. For comparison with the zero-width case, we let the width to be zero, and recalculate the mass of 0++ scalar glueball. It turns out that in the zero-width limit, and the results of the finite-width sum rules becomes automatically the corresponding results obtained in the zero-width sum rules. The con-tributions arising from the interactions between instantons and the quantum field are proven to be in-neglectable in 0++ -channel. In calculation, we have not only taken into account the case of quarkless QCD with contributions up to two loops and with a well-isolated lowest resonance, but also the case of QCD with three-light flavors up to three-loop levels with a single resonance below the mass scale of 2 GeV. Furthermore, in consideration of the admixture of f0(1370),f0(1500) and f0(1710) resonances, we have investigated the case of QCD with three massless quarks up to three-loop levels with three lower resonances. The results of Laplace sum rules indicate that the 0++ scalar glueball may lie around f0(1500) resonance, with mass, width and coupling to be m= 1.51±0.15 GeV,Γ= 0.12±0.04 GeV and f= 1.55±0.15 GeV, respectively. The corresponding Gaussian sum rules predict that the ranges of the mass, width and coupling may be m= 1.35～1.75 GeV,Γ= 0.03～0.60 GeV and f= 1.35-1.65 GeV, respectively.
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