At present, more and more pile caps use pipe pile to support,but the pipe pile will form a soil plug when driving into the soil layer.The effect of soil plug on vertical vibration feature of pipe pile cant be ignored.Through establishing pile vibration model considering soil plugging effect，the paper deduced the impedance function of vertical vibration and verified the rationality of solution.Then it discussed the effect of five factors such as pile material, slenderness, Poisson ratio, damping ratio and pile-soil relative stiffness on single pile impedance.The result shows that the five factors have a great influence on vertical dynamic characteristics of pipe pile, the result can provide some basis for engineering practice.