Based on the Veneziano ghost theory of QCD, we predict the cosmological constant D >, which is related to energy density of cosmological vacuum by . In the Veneziano ghost theory, the vacuum energy density rho (D >) is expressed by absolute value of the product of quark vacuum condensate and quark current mass: . We calculate the quark local vacuum condensates aOE (c) 0|: q: |0 > by solving Dyson-Schwinger Equations for a fully dressed confining quark propagator S (f) (p) with an effective gluon propagator G (A mu nu) (ab) (q). The quark current mass m (q) is predicted by use of chiral perturbation theory. Our theoretical result of D >, with the resulting aOE (c) 0|: 471-4 q: |0 > = -(235 MeV)(3) and light quark current mass m (q) a parts per thousand integral 3.29-6.15 MeV, is in a good agreement with the observable of the D > a parts per thousand 10(-52) m(-2) used widely in a great amount of literatures.