The wear characteristics of the trapezoidal fin against high-speed rotor were experimentally investigated at different final incursion depths, incursion rates, and sliding velocities. To characterize the geometrical effect, a small specimen (SS) and a large specimen (LS) were selected to analyze the mass loss, wear geometry, contact forces, and frictional temperature distributions under different conditions. The results show that the contact-separation is most likely to occur between the trapezoidal fin and rotor. In the rubbing process, the plastic deformation is dominating, and the abrasive and adhesive wears have pronounced effects on the wear behavior of the rubbing interface. The wear performance of the SS is sensitive to the structure imbalance, which induces the combined mushrooming and bending damage in the trapezoidal fin. However, the symmetrical mushrooming damage is generated in the LS. For both SS and LS, the mass loss is decreased with increasing incursion rate and sliding velocity, and the mass loss percentage is pronounced at the early stage of rubbing. The averaged friction coefficient is 0.1–0.16 for the LS whereas 0.1–0.19 for the SS. The peak frictional temperature is 560–640 °C for the LS, while 360–400 °C for the SS. The contact-separation significantly reduces the effects of final incursion depth, incursion rate, and sliding velocity on the wear geometry, contact forces, and temperature rise in the trapezoidal labyrinth fin.