The invention discloses a preparation process of a fiber reinforced resin based composite material transparent core rod for an overhead conductor. The preparation process comprises the following stepsof (1) thermosetting resin matrix modification; (2) transparent core rod finished product preparation. The transparent core rod prepared by the process conforms to national standards (GB/T29324-2012fiber reinforced resin based composite material transparent core rod for overhead conductor); the transparent core rod is in a transparent state under the light ray irradiation; the original inspection equipment is used; whether cracks or flaws exist in the core rod can be detected; the problems in the production process can be found in time and are solved; the economic loss caused by the defectsinside the conductor in the use process is greatly reduced; the use safety is improved.