The inhibition reactivity of two synthesized pyrazoline derivatives namely:1"Formyl"3"phenyl"5"(4"methylphenyl)"2"pyrazoline (P1) and 1"Formyl"3"phenyl" 5"(4"chlorophenyl) "2"pyrazoline (P2), towards steel corrosion was studied by using quantum chemical calculations and molecular dynamics simulation (MD) to give more insights into the action mode of studied inhibitors. Several parameters such as EHOMO, ELUMO, energy gap (ΔE), fraction of electron transfers (ΔN ) and Fukui index have been studied. Moreover, MD simulation is performed to simulate the best adsorption configuration of the investigated inhibitors on Fe (110) surface. Results indicate that the active sites of the molecules were mainly located on the pyarazoline ring and on the carbonyl group. The binding strength of the studied inhibitor molecules on Fe surface follows the orderP1>P2.