This work highlights two different strategies for functionalizing amino groups in MOF-808: directly binding amino acid to zirconium cluster and polyamine incorporation via nucleophilic substitution. The synthesized MOF-808-AAs and MOF-808-PAs exhibit remarkable CO₂ uptake capacity with amino group. Furthermore, under humidity condition, such capacity is greatly enhanced by dynamic breakthrough measurements. This research reveals that amine-functionalized MOF-808 are promising sorbents for direct air capture of CO₂ and propose a new strategy for functionalizing MOFs with post-modification for other applications.