1Piston design approach for automotive engines has been advanced from both experimental and calculation analysis. However, the developments of experimental analysis method that can verify the accuracy of the calculation analysis are required. In this paper, multi-point thin-film pressure sensor for piston pin-boss part (hereinafter pin-boss) was sputtered on piston pin sliding surface and oil-film pressure distribution was measured in axial and circumferential direction using the pin-boss fatigue tester. Two kinds of pistons with different pin-boss shape (tapered shape) were used in the experiment. The peak pressure of piston with large tapered shape was higher about 20%, compared to the piston with the small tapered shape. As a result of oil film pressure distribution in circumferential direction, it has measured that the oil-film pressure at near side relief was higher than that of piston top side.