In the present study, the steady incompressible turbulent flow in the ultra-highly loaded axial turbine linear cascade (UHLTC) with tip clearance was numerically analyzed by using the commercial CFD code focusing on the characteristic leakage flow in the tip clearance resulting in the formation of leakage vortex and the associated loss generation. The computed results indicated that the separation bubbles formed along the pressure surface and the first half of the suction surface on the blade tip surface influenced the loss generation related to the leakage vortex. Moreover, it was suggested that the effective loss reduction technique for the leakage flow was the squealer tip with the cavity distributed along the pressure surface on the blade tip surface.