Bresler-Scordlis beam was numerically analyzed to verify a finite element model proposed by ATENA. The simulated damage process and failure mode of Bresler-Scordlis beam and the experiment result are in good agreement. Then, 133 beams of Kani test were analyzed with the verified model. The ultimate load of simulated beams agrees well with the experiment data. From the further analysis of the simulation results of Kani beams, it can be found that the shear capacity contribution of arch action grows and the shear capacity contribution of teeth action reduces as the shear-span ratio increases. The nominal ultimate shear stress of the beams decreases with the increase of shear-span ratio. The curve turns obviously at the shear-span ratio of 2.5. The degree of the reduction before the turning point is larger than that after the point. When the shear-span ratio is larger than 2.5, the shear resistance of the beams with similar factors reduces slowly or even almost remains constant. However, the length of the shear span increases due to the growth of shear-span ratio. As a result, the maximum moment at failure increases, as well as the ratio of the moment and full flexural capacity. Hence, "The valley of shear failure" proposed by Kani has a rising branch as the shear-span ratio is greater than 2.5.