  We show how to calculate the effective potential of SU(3) QCD which tells
that the true minimum is given by the monopole condensation. To do this we make
the gauge independent Weyl symmetric Abelian decomposition of the SU(3) QCD
which decomposes the gluons to the color neutral neurons and the colored
chromons. In the perturbative regime this decomposes the Feynman diagram in
such a way that the conservation of color is explicit. Moreover, this shows the
existence of two gluon jets, the neuron jet and chromon jet, which can be
verified by experiment. In the non-perturbative regime, the decomposition puts
QCD to the background field formalism and reduces the non-Abelian gauge
symmetry to a discrete color reflection symmetry, and provides us an ideal
platform to calculate the one-loop effective action of QCD. Integrating out the
chromons from the Weyl symmetric Abelian decomposition of QCD gauge invariantly
imposing the color reflection invariance, we obtain the SU(3) QCD effective
potential which generates the stable monopole condensation and the mass gap. We
discuss the physical implications of our result, in particular the possible
existence of the vacuum fluctuation mode of the monopole condensation in QCD.
