The bending failure modes of and design requirements for Reinforced Concrete(RC) member strengthened with side-bonded Fiber Reinforced Polymer(FRP) are investigated through tests on its flexural behavior. With theoretical method of calculating flexural capacity on the positive section based on the assumption of plane section, a practical calculation method for the flexural strength reinforced with side-bonded FRP is put forward. The calculated values, which are well consistent with the test data, are reliable and  can be referential for  designers. The study also probed into the values of correction coefficient ηf in Design Code for Strengthening Concrete Structure (GB 503672006) when FRP is bonded on the sides of RC beams rather than on the bottom. When hf/h is a fixed value, the correction coefficient ηf is not a definite value as shown in the design above code, but varies with the parameters of the strengthened RC beams.