In this dissertation, material properties of high strength concrete and the shear strength of reinforced high strength concrete beams are investigated experimentally, and a rational and accurate equation for prediction of shear strength of reinforced concrete beams is derived based on basic shear transfer mechanisms and modified Bazant``s size effect law. For the structural application of high strength concrete, several material properties such as long-term strength and workability of fly ash high strength concrete, strength development of high strength concrete containing silica fume, and flowing characteristics of flowing high strength concrete are firstly investigated. Twenty singly reinforced high strength concrete beams without web reinforcement are tested to investigate their behavior and to determine their ultimate shear capacities. Test variables are longitudinal steel ratio, shear span to depth ratio, and effective depth. Test results are analyzed and compared with the strengths predicted by ACI code equation, CEB-FIP model code equation, Zsutty``s equation, Bazant``s equation, and the proposed equation. ACI code equation underestimates the effects of longitudinal steel ratio and shear span to depth ratio, and is not safe for the largest beams. Within the scope of this study, there is not clear difference in size effect with increasing compressive strength of concrete. The proposed equation includes the effects of concrete strength, longitudinal steel ratio, shear span to depth ratio, and effective depth. To reflect the varying effect of concrete strength, failure mode index is introduced. The proposed equation is compared to several well-known equations with extensive experimental data available in the literatures. As a result, the accuracy of the proposed equation is better than that of any other equation. In addition to the originally proposed equation, a simplified design equation is also derived for practical use within the limited range of effect...