Newly synthesized trimeric cationic surfactant namely; N,N'-(((2-(2-((1-(dodecyldimethylammonio)propan-2-yl)oxy)-2- oxoethyl)-2-hydroxysuccinyl) bis(oxy))bis(propane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium) bromide; (ADPC12) and its chemical structure has been certain by FTIR and 1HNMR spectroscopic analysistechniques. Gravimetric and electrochemical testes suggested the inhibition affinity of the prepared tested compound. Tafel curves suggested that the tested ADPC12 acted as mixed-type effective inhibitor. The inhibitor efficiency increased by increasing the inhibitor concentration, reaching 90.03% at 1x10-4M. The inhibitor behavior study of ADPC12 is returned in to its adsorption affinity and follows Langmuir adsorption isotherm. Surface morphology study verified the adsorption of ADPC12 on X-65 steel surface. Thermodynamic activation parameters were calculated and discussed thoroughly.