Theoretical modeling of ionization potential depression (IPD) and the related ionization equilibrium in dense plasmas, in particular, in warm/hot dense matter, represents a significant challenge due to ionic coupling and electronic degeneracy effects. Based on the dynamical structure factor (SF), a quantum statistical model for IPD in multi-ionic plasmas is developed, where quantum exchange and dynamical correlation effects in plasma environments are consistently and systematically taken into account in terms of the concept of self-energy. Calculations for IPD values of different chemical elements are performed with the electronic and ionic SFs. The ionic SFs are determined by solving the Ornstein–Zernike equation in combination with the hypernetted-chain closure relation. As a further application of our approach, we present results for the charge state distribution of aluminum plasmas at several temperatures and densities through solving the coupled Saha equations.