Based on the soft soil foundation of Tianjin Binhai New Area,the change of pile group effect coefficient in different pile length,pile diameter,pile spacing and different number of pile were analyzed by using the finite element software MIDAS. The result shows that the pile group effect coefficient decreases as the increase of the pile length,pile diameter and pile number. The pile spacing has little effect on the pile group effect coefficient. The load ratio shared by the soil under the cushion cap increases as the pile spacing,the pile diameter decreases and as the pile length,pile number increases.