The invention relates to a device and a method for manufacturing an optical fiber preform rod by using an OVD technology. The device comprises a deposition cavity, wherein the top part and the lower part of the deposition cavity are correspondingly provided with upper and lower synchronously-rotating chucks which are used for clamping to-be-sprayed core rod; equidistantly-spaced blast lamp assemblies, corresponding to the upper and lower synchronously-rotating chucks, are vertically arranged at one side of the deposition cavity and connected with a slide seat which moves up and down; and an air suction opening, corresponding to the blast lamp assemblies, is arranged at the other side of the deposition cavity. The device is characterized in that a laser diameter measurer is arranged at theouter side of the deposition cavity; the output end of the laser diameter measurer is connected with a PLC; the control end of the PLC and a chuck rotation control system are connected to realize real-time feedback regulation and control of the outer diameter of a powder rod and the rotating speed of the rotating chucks; thus, linear velocity at the intersection position of a powder rod depositionsurface and a flame center drop point remains constant in the whole process of deposition. The device and the method provided by the invention can improve the overall uniformity and collection rate of the powder rod, and improves the OVD manufacturing efficiency and quality of the powder rod; and a feedback device provided by the invention is simple and reliable, can be easily implemented, has strong stability, and is applicable to mass production.