The impact of mechanical strain is studied at CO-poisoned Pt(111) surface for hydrogen adsorption. Our experiment first investigates a coupling parameter of interest, zeta(H), which quantifies the variation of hydrogen adsorption potential in response to surface strain. The result exhibits a bigger zeta(H) at CO-poisoned surface than the value measured at clean surface. Since adsorption potential is linked to adsorption energy, it indicates significantly the larger effect of tensile strain on decreasing hydrogen adsorption energy at CO-poisoned surface, comparing to the clean surface. OFT calculations at an atomic level support the experimental observation and explain this behavior can be attributed to the strain-induced reduction in CO-poisoning effect on hydrogen adsorption energy. (C) 2017 Elsevier Inc. All rights reserved.