New advanced investigations of aluminum properties at extreme conditions include experiments and theoretical calculations. Experimental researches on shock and isentropic compression of aluminum at high pressures up to 500 GPa have demonstrated smooth monotonic dependencies, resulting in more “stiff” compression curve and shock adiabat for aluminum that it was figured in previously. Adiabatic‐expansion measurements of shocked aluminum have brought new accurate data for the region of hot expanded liquid. Theoretical “ab initio” QMD calculations in the region in the vicinity of the critical point established the reference domain of thermodynamic data. This complex of data serves as a fundament for a new multi‐phase EOS for aluminum.