Abstract: The test results of prototype and model of pile group with different pile spacing and pile length in silt andsoft soil under vertical load are intreduced in this paper。The test results have indicated:the deformation behaviour ofpile group in homogeneous soil varies with pile spacing the compressive deformation of soil between piles increasesas the pile spacing increases;the compressive deformation and depth of compressive zone below pile bottom decreaseas pile spacing increases;the interaction of pile-pile and pile-soil are less than those predicted by elastic theory.Based on the analysis of test results,this paper raises two improvement propositions with respect to the methods of settlement cal culculation for pile group :①the bearing base of pier is determined prDperly according tO the pilespacing,pile length and bearing stratum characteristics in equivalent pier methed;②the interaction coefficient ofpiles and settlement ratio of pile group in elastic theory methed for calculating settlement are modified.