Abstract: The reasonable calculation method of thrust force and its influencing factors were studied by applying mathematics and mechanics based on the working mechanism of EPB shield machine.Model experiments on thrust force during tunnel excavation with EPB shield machine under different conditions of burying depth,cutter opening rate and soil property were carried out.The aforementioned theoretical results were also verified.Combining with a subway tunneling case,the derived formula was used to forecast the values of thrust force in the course of shield tunneling,and satisfactory results were achieved.