The phase structure and element distribution of surface of ZrCo alloys with Ti modification were investigated by EDS and XRD. Effect and mechanism of Ti modification on hydrogenation behavior of ZrCo alloys with poisoned by CO was investigated via TOF-SIMS and TPD. The results showed that the hydrogenation period of ZrCo and Zr0.8Ti0.2Co alloys are less than 2 minutes and 4 minutes under the pure hydrogen atmosphere, and the capacity of hydrogenation could reach 1.8wt% and 1.9wt%, respectively, whereas the capacity of hydrogenation of ZrCo and Zr0.8Ti0.2Co just obtained 0.91wt% and 0.48wt% within 2500 minutes in the presence of CO contaminant gas, which meant the hydriding kinetics of ZrCo decreased with Ti modification. And performance of posioned sample could revert with treatment of vaccuming at 773K for 0.5h