holographic QCD model is trying to describes phenomenology of real QCD in the case of $N_c=3$. In some sense, this is under a more general holographic conjecture for gauge/gravity duality [@tHooft:1993dmi; @Susskind:1994vu].

The full QCD contains quark dynamics and gluodynamics, and it is known that light flavor quark dynamics are responsible for the spontaneous chiral symmetry breaking, and gluodynamics are responsible for the color confinement. The dynamical holographic QCD model is constructed in the graviton-dilaton-scalar framework with the dilaton field and scalar field responsible for the gluodynamics and chiral dynamics, respectively. This dynamical holographic QCD model naturally resembles the renormalization group from ultraviolet (UV) to infrared (IR): at UV boundary, the theory goes to the limit of AdS/CFT, and the 5-dimension (5D) field in the bulk and 4D operator obeys the principle of AdS/CFT correspondence [@Erlich:2005qh], and the model at IR is determined by QCD non-perturbative properties such as chiral condensate and gluon condensate or glueball properties. In [@Li:2012ay; @Li:2013oda; @Chen:2015zhh; @Li:2014dsa; @Li:2014hja], we see that the graviton-dilaton system can describe the pure gluon system including the glueball spectra, thermodynamical properties as well as transport properties quite well. After adding the flavor background and solving the deformed metric self-consistently, the 