The corrosion resistance of a 400 MPa Cr-Mo alloyed corrosion-resistant HRB400cE steel bar and an ordinary HRB400E carbon steel bar in a neutral chloride environment was studied through weekly immersion corrosion experiments and electrochemical experiments. The morphology and composition of the rebar rust layer were analysed by scanning electron microscopy and X-ray diffraction. The results show that after accelerated corrosion in a 2 wt. %NaCl solution, the new chromium-alloyed corrosion-resistant rebar has better resistance to chloride ion corrosion than ordinary carbon rebar and the corrosion rate in the alternate immersion test is 67% of that of ordinary rebar. After accelerated corrosion, the ordinary carbon rebar exhibits a thicker rust layer with a loose structure, while the chromium-alloyed corrosion-resistant rebar exhibits a thinner rust layer with a multilayer dense structure. Compared to the HRB400 rebar, the HRB400cE rebar has a higher corrosion potential, lower self-corrosion current, and lower electrochemical corrosion rate, exhibiting good corrosion resistance in environments with different chloride concentrations.