Currently, Development of high strength reinforced concrete HSRC applications worldwide is going faster than the researches on it. Where, the shear mechanism of deep beams without stirrups still fully not understood due to its complicated behavior and conditions. In this paper, a comparative study on the shear mechanism of RC deep beams by considering values of current experimental shear strength and those calculated by international design approaches; ACI, CSA & FIB and also by the equations proposed by Sudheer, Zararis, Bazant, Zsutty, Russo and Shah. Eighteen simple span HSRC deep beams , practical size, without stirrups were tested under monotonic two point loads at the mid span to examine the contribution of various parameters on the shear capacity of deep beams. f’c=80 MPa, (ρs%) three values of main steel ratio (0.73%,1.21% &1.83%), (a/d) shear span to effective depth ratio ( 2,1.5 &1) and constant beam width for all tested beams “b= 250” mm were selected to mainly study the shear capacity and behavior of HSRC deep beams, where typical shear failure can be anticipated. As a conclusion of this paper, ACI and FIB code provisions for shear in High strength concrete (HSC) are safe for use with the exception that CSA should be used with care. Despite numerous studies, there is still a need to develop a clear understanding of the shear behavior of practical size of HSRC deep beams without web reinforcement. Therefore, this experimental program was arranged to evaluate the shear behavior and to increase the shear database on HSRC deep beams.