This paper involves a destructive full-scale load test on long bored pile instrumented with strain gauges along the shaft. The load-displacement response, the distribution of axial force, and the thresholds of displacement for fully mobilizing the skin resistances in different soils in tension case were discussed in this paper. The field test results show that the measured tip resistance in the pile under tension is near zero during the whole loading, and the softening is accompanied with a reduction in skin friction when the skin friction is fully developed. It also can be investigated that the threshold of displacement for fully mobilizing skin friction is different even if in the same soil type due to different soil stress states. Generally speaking, the thresholds of relative pile-soil displacement for fully mobilizing skin frictions in the sandy silt, silty sand mixed silt, silty clay, silty clay mixed sand and gravel are about 4 mm, 11 mm, 7 mm, 6 mm, and 5.5 mm, respectively.