In this study, a trailing edge cutback film cooling model with latticework ducts is proposed. The dynamic mechanisms of unsteady flow characteristics and film cooling efficiency of trailing edge cutback at five blowing ratios (M), which are controlled by the deflected swirling coolant induced by the latticework ducts, are investigated using the DES (Detached Eddy Simulation) method. The results show that the cooling efficiency exhibits a fluctuating peak-valley distribution as the blowing ratio increases. At M=1.25, the area-average cooling efficiency reaches 0.646. Under higher blowing ratios, the mixing process is dominated by swirling coolant downstream of the cutback. Large-scale counter-rotating vortex pairs are observed in the spanwise section. Additionally, the swirling jet induces the generation of rotating streamwise vortices, significantly affecting the distribution range of the film coverage on the wall.