The pile-soil stress ratio and the lateral displacement of plastic tube cast-in-place concrete pile with supporting disc(TC pile with disc) in the engineering of bridgehead segment was investigated by relying on road engineering in Shanghai and laying the relevant test equipment in the engineering of bridgehead segment. Based on persisted data monitoring,the TC pile with disc's pile-soil stress ratio distribution was obtained from the measured data with scientific analysis. It was found that it is hard to form soil arching under the lower embankment; and the soil under roadbed has a long soil return extrusion because of the construction process. Then the paper pointed out that after the TC pile with disc completed should apply enough load and continued enough time,make the soil around the pile to fully return extrusion,so that the TC pile with disc can full play its strength,reducing the bridge section settlement.