Abstract: On account of a long-term observation of subgrade subsidence after construction in a certain coastal dredger fill region and Subsidence prediction using hyperbolic fitting method, the measured settlement and predicting subsidence of High vacuum compaction method and Board ground stability technique were analyzed. The results show that the average measured final settlement is 53 mm and 61 mm respectively, predicting subsidence was between 100 mm to 150 mm. Two kinds of method can better control post-construction settlement, but High vacuum compaction method processed sections are smaller and faster to post-construction settlement. in terms of Cost ,high vacuum tight treatment cost about 85 Yuan/m² of 6 m depth, the Board ground stability technique of 80 cm cost reaches 80 Yuan/m², It shows that the High vacuum compaction method treatment effect has more advantages on the post-construction settlement, treatment depth, the processing cost and so on, and is more suitable for popularization and application in the region.