Abstract: Simplified the force state of drilling tool in raise boring machine under reaming process which is based on extremely hard rock in iron mine.Study on force in drilling tool under reaming process must take into account many factors sand obtained the pulling force and torque force formula of drilling tool.The factors not only include vibration load of ream bit and occasional load, but also interaction between drilling tool and rock stratum.It is proved to achieve good results that the application of the pulling force and torque force formula which based on the analysis of rock compressive strength.The engineering practice application shows that research results are worth learning and promoting when study on pulling and torque force in drilling tool under reaming process.