Abstract: CO often coexists with N₂, CH₄, CO₂ and H₂O. In order to purify CO gas, Ni-MOF-74 material was used as adsorbent to carry out exploratory research. Ni-MOF-74 hydrophobic material was prepared by PFAS (perfluoroalkylsilane) immersion. The surface hydrophobicity and morphology of Ni-MOF-74 were analyzed by means of contact angle measuring instrument, SEM and FT-IR. The effects of immersion temperature, immersion concentration, immersion time, and immersion number of times on hydrophobicity were discussed. The influence of hydrophobic modification on CO adsorption performance was also studied. The experimental conditions of PFAS immersion were determined: The immersion temperature is 110 ℃, the immersion time is 24 h, the immersion number of times is 1, and the concentration of PFAS is 3%. The results show that PFAS is successfully coated on Ni-MOF-74, but only a few of them covers the surface of Ni-MOF-74. The crystal structure of Ni-MOF-74 modified by PFAS is partially destroyed and the thermal stability is reduced.