The quantum mechanical approach is becoming more desirable tool for predicting the mechanism of inhibition by compounds. The inhibition efficiency of sulphur containing organic compounds is dependent on many basic molecular descriptors include: dipole moments, electronic parameters as EHOMO (highest occupied molecular orbital energy); ELUMO (lowest unoccupied molecular orbital energy); ΔE, energy gap (ELUMO- EHOMO). A chemdraw 3D simulation technique was used to run the quantum mechanical analysis and established correlation's between different types of descriptors and measured corrosion inhibition efficiency for thiourea derivatives. The use of this method substantiates the inhibition efficiencies of the compounds determined by electrochemical methods.