Abstract: The results of model tests on pile-soil-cap interaction were presented.The soil displacement among the piles,contact pressure on the base of the cap,pile shaft and toe resistance were studied.It was observed that the ratio of pile toe penetration to foundation settlement decreased with the increase of pile number under the same foundation loading.With the same soil displacement among the piles,the contact pressure on the base of pile cap was larger for the foundation with two piles than that with single pile because of the enhancing function of the two piles on the soil capacity beneath the pile cap.The relative displacement between pile and soils around pile shaft was developed from the pile toe and gradually spread to near the pile cap.The relative displacement between pile and soils around pile shaft outside the foundation was larger than inside the foundation at the same depth.The mobilization of shaft resistance and its ultimate value of the shaft inside the foundation were different with those outside the foundation.With the same soil displacement among the piles,the vertical soil stress at the depth of pile toe was larger for the foundation with two piles than that with sing pile,which resulted in larger toe resistance for the foundation with two piles.