The utility model relates to a testing device of a core rod. The testing device comprises a test equipment clamp, a core rod, a test equipment laser, a guide rail and an equipment lower limit position. The test equipment clamp is used for clamping the core rod and can move downwardly along the guide rail to the lower limit position. The testing device further comprises an auxiliary apparatus which is placed on the upper end of the core rod and used for assisting data detection of the core rod. The auxiliary apparatus includes a handle, a clamping block and a holding filament, wherein the handle is in connection with the clamping block and the clamping block is used for clamping the core rod which is further fixed through the holding filament. The upper end of the core rod is additionally provided with the auxiliary apparatus that assist detection of the core rod, so data about the geometric dimension and optical parameters of the core rod is guaranteed to be complete, and the detection efficiency is improved.