Corn straw can be converted to bio-oil through pyrolysis. However, the application of bio-oil is severely restricted due to the high content of oxygen. Catalytic pyrolysis is an available way for deoxygenation of bio-oil, and the deoxygenation reactions are strongly dependent on the type of catalyst. Whereas, the correlation between the deoxygenated products and the catalyst types is still far from clear. In this work, the migration of O in the pyrolysis process was investigated, and eight catalysts were screened for deoxygenation of bio-oil, with a lab-scale fixed-bed reactor. The results showed that with the increase of pyrolysis temperature, the content of O in bio-oil decreased below 400 ℃ and then became stable and finally increased rapidly after 550 ℃, indicating that the range of 400-550 ℃ was the proper temperature for deoxygenation. Eight catalysts (ZSM-5, SAPO-34, ZnO, MgO, δ-Al2O3, γ-Al2O3, acidified-α-Al2O3 and acidified-γ-Al2O3) were tested, and it was found that a higher alkalinity of catalyst was favorable for decarboxylation of bio-oil with more produced CO2, while a higher acidity was promoted the decrease of alcohols and carbonyls with more generation of H2O and/or CO. MgO was judged as the optimal catalyst for deoxygenation of bio-oil. The quality of bio-oil under the catalysis of MgO was best, with higher H/C and lower O/C.