In this paper, we reanalyze the I = 0 scalar channel with the improved Monte-Carlo based QCD sum rules, which combines the rigorous Hölder-inequality-determined sum rule window and a two Breit-Wigner type resonances parametrization for the phenomenological spectral density that satisfies the the low-energy theorem for the scalar form factor. Considering the uncertainties of the QCD parameters and the experimental masses and widths of the scalar resonances σ and f0(980), we obtain a prediction for light quark mass mq(2 GeV) = 1 2 (mu(2 GeV) + m d (2 GeV)) = 4.7 +0.8 −0.7 MeV, which is consistent with the PDG (Particle Data Group) value and QCD sum rule determinations in the pseudoscalar channel. This agreement provides a consistent framework connecting QCD sum rules and low-energy hadronic physics. We also obtain the decay constants of σ and f0(980) at 2 GeV, which are approximately 0.64 − 0.83 GeV and 0.40 − 0.48 GeV respectively.