The work aims to study corrosion characteristics of X65 steel by immersion experiment and corrosion image representation under the combined action of Cl- and DC stray density. Uniform corrosion rate of X65 steel was calculated in loss weight method and by immersion experiment under the influence of Cl- and direct current density. Corrosion morphology after immersion was observed with three-dimensional microscope to verify main corrosion morphology and its law of development. Provided with different Cl- concentration, the uniform corrosion rate of X65 steel almost remained unchanged and the error was mainly due to insufficient cleaning of corrosion products and water absorption difference of epoxy resin. Corrosion rate was proportional to direct current density, and main effect of Cl- was to produce different local corrosion characteristics on the specimen, thus damaging uniform corrosion on specimen and intensifying local corrosion, but having no effect on overall corrosion rate. Direct current density outflowing from pipe, rather than the environment conditions, from pipe is the main cause of pipe corrosion weight loss. Low Cl- concentration is the main cause of local corrosion of X65 steel. With the increase of Cl- concentration, the corrosion form gradually turns into uniform corrosion. Corrosion caused by direct current density is mainly uniform corrosion.