The invention discloses a production method of a reverse magnetic optical fiber core rod applied to an optical fiber current transducer. The production method comprises the following steps: producing a preliminary perform rod with a preset fiber core refractive index by adopting a vapor deposition process; obtaining an outer diameter target value of the perform rod during wire drawing according to the preset optical fiber size and the core size of the perform rod; producing a finally-used perform rod by adopting a rod nesting technique according to the outer diameter target value of the perform rod during wire drawing. According to the preparation method disclosed by the invention, the reverse magnetic optical fiber core rod which meets service demand and is applied to the optical fiber current transducer can be simply and efficiently produced.