In this paper, the shear-improved Smagorinsky model (SISM) is assessed in a K-type transitional channel flow. Our numerical simulation results show that the original SISM model is still too dissipative to predict the transitional channel flow. Two former reported empirical correction approaches, including a low-Reynolds-number correction and a shape-factor-based intermittency correction, are applied to further promote the capability of the SISM model in simulating the transition process. Numerical tests show that the shape-factor-based intermittency correction approach can correctly improve the transition-prediction capability of the SISM model, while the low-Reynolds-number correction approach fails. Furthermore, the shape-factor-based intermittency-corrected SISM model can capture the vortical structures during the transitional process very well and possesses the grid-insensitive characteristics.