Theinhibitioneffectoftwopyrimidinederivatives,2-hydroxypyrimidine(HP)and2mercaptopyrimidine(MP),onthecorrosionofcoldrolledsteel(CRS)in1.0−5.0mol•L −1 HClisinvestigated bymassloss,potentiodynamicpolarizationcurves,electrochemicalimpedancespectroscopy(EIS),and quantumchemicalcalculations.TheresultsshowthatHPandMParebothgoodinhibitorsofcorrosionof CRSin1.0mol•L − 1 HClsolution.TheadsorptionoftheseinhibitorsontotheCRSsurfaceobeystheLangmuir adsorptionisotherm.Inhibitionefficiencyincreaseswithinhibitorconcentration,anddecreaseswith hydrochloricacidconcentration.Thethermodynamicparametersofadsorption(adsorptionequilibrium constant( K )andadsorptionfreeenergy( Δ G 0 ))andkineticparametersofcorrosion(apparentactivation energy( E a ),pre-exponentialfactor( A ),corrosionrateconstant( k ),andkineticreactionconstant( B ))are alsocalculated.Basedontheseparameters,themechanismofinhibitionisdiscussed.Potentiodynamic polarizationcurvesshowthatHPandMPactasmixed-typeinhibitors.EISexhibitonecapacitiveloop,and thechargetransferresistanceincreaseswithinhibitorconcentration.Theresultsofquantumchemical calculationsindicatethatMPexhibitshigheradsorptiveabilitythanHP,whichisingoodagreementwiththe experimentaldata.