Using the detailed configuration accounting with the term structures treated by the unresolved transition array model, we present a method to calculate the transmission spectra of hot dense plasmas. Due to the fully relativistictreatment, incorporated with the quantum defect theory to calculate the atomic parameters of the huge number of configurations with high principal quantum number, we can study the opacities for any middle- and high-Z plasmas with much less computational efforts.We can also conveniently identify the dominant configurations and the detailed features of transition arrays, which are very helpful for the diagnostic of the plasma conditions.The accuracy of our theoretical model is tested by comparing the calculated transmission spectra of Fe and Ge plasmas with the bench mark experimental data.