[en] The critical current $I_c$ and vortex glass (VG) transition of K_0.62Fe_1.71Se₂ crystal have been studied via measuring the current-voltage $(I\text{-}V)$ characteristics by rotating the crystal around its c-axis in magnetic fields parallel to the ab-plane. It is found that the $I\text{-}V$ curves show a good three-dimensional VG scaling collapse. The $I_c$ and VG transition temperature $T_g$ exhibit a distinct fourfold symmetry due to the in-plane fourfold superconducting stripe structure in the nanoscale phase-separated system. The $I_c$ is clearly enhanced for fields parallel to the superconducting stripe owning to the increased $\mathrm{\delta <!--\; ??\; -->}{T}_c$ pinning associated with the nanoscale phase separation. (letter)