Abstract: Through the bending load test of 4 grouting material width replacement reinforced RC beams, the influence of width reinforcement method on the failure modes, bending moment-deflection curve, and strain distribution of concrete (grouting material) in the mid-span section was compared and analyzed. The results show that the grouting material side of the single-sided replacement beam cracks earlier and the cracks in the pure bending section are denser, and the concrete side of the top of the beam is damaged first. Compared with the single-sided replacement beam, the double-sided replacement beam has a larger cracking load, a smaller width and a slower development, and the difference in crack development between the two in the later stage of loading is small. When the longitudinal bars at the bottom of the beam yield at the ultimate load stage, the double-sided replacement beam has the largest load growth. Compared with ordinary concrete beams, the cracking loads of the two width replacement beams are reduced to varying degrees, the yield loads do not change much while the yield deflections increase slightly, the ultimate loads increase slightly while the ultimate deflections increase significantly. The tensile longitudinal bars on both sides of the single-sided replacement beam yield almost simultaneously. During the bending process, the strain of the concrete (grouting material) in the mid-span section of each beam specimen basically conforms to the flat section assumption. The neutral axes of the single-sided replacement beam are very close at the cracking load and ultimate load. Based on the difference between single-sided and double-sided width replacement reinforcement, a calculation method for the cracking load and bending bearing capacity of grouting width replacement reinforced RC beams is established, and the calculated values are in good agreement with the experimental values. This study can provide a reliable theoretical basis for the improvement of RC structure reinforcement theory.