For safe physical human- robot interaction,a method of statics analysis on safe manipulator based on torque limiter is proposed. It is very important to analyze the maximum isotropic force and the maximum achievable force. After a series of derivation,the relationship and operation steps among the joint limit torque and the maximum isotropic force and the maximum achievable force are obtained. And the ratio of the maximum isotropic force and the maximum achievable force is proposed as a safety performance index applied in redundant manipulator kinematics to perform tasks effectively. Finally,through the MATLAB algorithm programming,the simplicity and effectiveness of the method steps are verified by numerical examples,which provide a control theoretical basis for manipulator architecture and configuration to calibrate torque limiter.