Reinforced concrete specimens with concrete compressive strength varied from 46.5 to 50.6 MPa and with depth of cross section from 250 mm to 1 000 mm subjected to bending were tested. Size effects of flexural behavior with respect to bending capacity and deformation capacity were investigated based on the analysis of the test results and those of high-strength specimens (fcu=72.1~72.4 MPa) of which the geometry and reinforcement layouts were identical to those of specimens tested in this study. It is shown that beam depth does not has any apparent influence on nominal cracking moment， nominal yield moment and nominal ultimate moment， and that it has significant influence on displacement ductility and plastic rotation capacity of plastic hinges of members. For normal-strength concrete specimens and high-strength concrete specimens， both the displacement ductility and the plastic rotation capacity decrease with the increasing of depth in the similar ways， and are independent of concrete strength. It is also demonstrated that the lengths of plastic hinges of members with different depth and concrete strength are approximately equal to the depth.