Abstract: The corrosion behaviors of three kinds of carbon steels 20^#, 20G and L360NB commonly used in oil and gas gathering and transportation pipelines were studied by electrochemical corrosion test and high temperature and high pressure dynamic corrosion test under simulated conditions of typical oil and gas gathering and transportation on site. The results show that under normal temperature and pressure conditions, the electrochemical corrosion behaviors of the three kinds of pipes were relatively close, but 20^# and 20G steels were more prone to corrosion. Under the condition of high temperature and high pressure in the simulated field, the three steels exhibited obvious uniform corrosion and pitting corrosion, the corrosion rates were relatively close, the difference of corrosion morphology was small, and the rates of pitting corrosion for the three steels were higher than those of the uniform corrosion. It could be seen that the development rate of pitting corrosion was more harmful to the whole pipeline than uniform corrosion.