The invention discloses an assembling and positioning method used for an iron roughneck plier guiding rail. The assembling and positioning method comprises the steps that the guiding rail on clamping pliers is assembled and positioned; firstly, a tool with the corresponding dimension is manufactured according to a theoretical installation position of the guiding rail of the clamping pliers; secondly, two sliding block assemblies in the clamping pliers are turned and rotated through 180 degrees leftwards and rightwards correspondingly and then installed in a plier body of the clamping pliers in the opposite direction; thirdly, the tool is connected with the sliding block assemblies through hinge pins; fourthly, the alignment condition of the tool and a bite of the clamping pliers is checked; and finally, the guiding rail in the clamping pliers is attached to the excircle of the tool tightly and placed firmly, then the guiding rail is welded according to welding technological requirements, and positioning is achieved. The invention further discloses an inspecting method used for the iron roughneck plier guiding rail. The two methods are simple, and convenient and easy to execute, the accuracy of positioning the iron roughneck guiding rail is improved, and the working efficiency is improved.