The invention relates to a preparation method for a core rod for a seamless steel tube and the core rod for the seamless steel tube. The preparation method mainly comprises the steps of steel ingot casting, initial homogenization treating, diameter forging stock fabricating, secondary homogenization treating, core rod blank preparing, grain refinement treating and the like. By means of the preparation method for the core rod for the seamless steel tube, two-time high temperature diffusion homogenization, diameter forging stock fabricating and core rod blank forging are combined organically, dynamic conditions conducive to the diffusion of carbon and alloy elements are created, the core rod material matrix tissue with the carbon and alloy elements being extremely uniformly distributed in the steel material matrix is obtained in the same or shorter homogenization time, the prepared core rod is made to have the characteristics of high tenacity, high red hardness and long service life, andthe core rod is good in performance.