Abstract: To improve the crack resistance and mechanical properties of reinforced concrete (RC) beams, textile and modified concrete are used to strengthen RC beams. Proposed through force analysis are the theoretical calculation methods of load-deflection curve, of flexural capacity, of shear capacity, and of crack width of RC beams strengthened with textile and modified concrete. Considering the influence of textile, anchoring measures, modified concrete types, and modified concrete pouring thickness, 12 RC beams are designed and manufactured for tests. The test results show that both carbon textile and modified concrete can improve the crack resistance and mechanical properties of RC beams, that the combination of carbon textile and modified concrete has the best effect, and that the maximum strengthening effect of bearing capacity can reached 39.04%. Among the two kinds of modified concrete, the strengthening effect of modified concrete without rubber particles is better; and the proposed anchoring measures can effectively avoid the debonding of the textile reinforcement layer. The strengthening effect of modified concrete on the mechanical properties of RC beams gradually decreases with the increase of pouring thickness, and the related parametric analysis results determine that the optimal pouring thickness of modified concrete is 64%. Based on the test results and on the finite element analysis method, verified are the validity of the proposed calculation methods of load-deflect curve, of flexural capacity, of shear capacity, and of crack width.