Abstract: The corrosion wear behavior of oil well tube steel P110S in NaCl solutions at different pH was investigated by the mass-loss and electrochemical tests. The wear products on the sample surface were also analyzed. The results show that the corrosion wear rate of the tested steel in NaCl solution at pH3 was the highest while the lowest in NaCl solution at pH7. In NaCl solutions at different pH, the synergy between corrosion and wear of the tested steel was positive. The free corrosion potential of the sample after corrosion wear was the lowest in NaCl solution at pH11 and had little difference in NaCl solution at pH3 and pH7. The solution pH value had little influence on the free corrosion potential of the sample before corrosion wear. With the increase of NaCl solution pH value, the wearing deformation at the sample surface increased, and the atom ratio of O/Fe of the corrosion product decreased.