Abstract: The Janssen equation has been used to calculate the pressure variation at ore pass bottom during ore drawing process. However, the result calculated with the Janssen equation is usually larger than the practical one. According to the numerical analysis and laboratory tests, it is found that the pressure at the bottom maintains a certain value and it does not changes with the ore body height in the drop shaft. Based on the laboratory test data, the formula used to calculate the pressure at the bottom under the third kind of static pressure condition during ore drawing process is proposed. Comparing with the laboratory test results, the formula can well predict the pressure at the bottom of the ore pass and it provides the referential research basis for the flow patterns of the ore body during its drawing process.