Abstract: The offset wrist robot with prismatic link for mining equipment can withstand large loads and has a large operating rangeIn this paper，this type of robot is studied，and two characteristics of its architecture are foundOne is that the solution for the fifth degree of freedom is equivalent to the solution for the angle between a special line and a special planeThe other one is that the distance from the origin to the intersection of vector axis 3 and vector axis 4 is a fixed valueThe two characteristcs make it possible to obtain the solution of the fifth and sixth degrees of freedom by iterative searching methodA new method of robot kinematics solution is proposedIt is not necessary to establish the coordinate frames attached to all the linksThe whole calculation process is completed in the global coordinate systemThe forward kinematics is completed step by step in sequence and，the inverse kinematics is completed step by step by returning methodThe new method has the advantages of short calculation time and high accuracy，which solves the problem that the traditional numerical method is not conducive to industrial application and promotes the application of the Pieper robot which has offset wrist with prismatic link in the welding of cutting head and underground drilling.