Abstract: Th is paper is based on the characters o f soft clayey soils and observed sett lem ent data of one highw ay in L ianyungang area. It ana lyses the affecting factors of the in- data accumu lated sett lement through sing le factor a nalysism ethod andmu ltifactor ana lysis method. It takes in to considerat ion of the fine settlement and conso lidation effec.t Pseu- orthogonal design me thod is put forw ard, and is used in the actual pro jec.t The resu lts conc lude: preloading method and the height of filled so ilhave reasonab le affects to composite foundat ion settlement in th is pro ject on th is seaside clay area. A s a resu l,t it is suggested that ad just pre load ing method and control the he ight o f filled so il at f irst in the area where the range of thickness of soft c layey is sma l.l