Abstract: Based on model test of pile group, the changes in excess pore water pressure are measured as single pile and pile group are pressed; the dissipation and distribution of excess pore water pressure as well as effect of construction order are analyzed. The excess pore water pressure is continuously accumulated wi th increasing of pile's number, but this tend is getting slower. In horizontal direction, excess pore water pressure nonlinearity decreased wi th increasi ng of the distance between measuri ng point and pile's axis. The effect range of excess pore water pressure i s within 5D (herein D is the diameter of pile). The excess p ore water pressure con tinuously increased along depth and the increment of lateral side is much greater than that in the region of pile group. The dissipation of excess pore water pressure is related to the soil's permeability and dissipation is a slow process. Measures for discharg i ng pore water should be adopted to reduce soil squeezing effect in pile group cons truction