The invention relates to a method for preparing a single mode fiber core rod with a PCVD (plasma chemistry vapor deposition) process at a high deposition rate. The method is characterized in that a pure quartz lining tube is placed in a microwave resonant cavity heat preserving furnace and penetrates through a cylindrical microwave resonant cavity to rotate periodically, and the microwave resonant cavity performs axial reciprocating motion relative to the pure quartz lining tube; mixed gas enters the tube from one end of the lining tube, the variety and the flow of the mixed gas are shown as follows: 500-3,000 sccm of pure silicon tetrachloride steam, 2,000-8,000 sccm of pure oxygen, 10-200 sccm of germanium tetrachloride steam and 0-50 sccm of Freon; the other end of the lining tube is a gas discharge end, the gas discharge end is connected with a vacuum pump, and the internal pressure of the lining tube is controlled to be at10-30 mBar; the deposition rate in the lining tube is 2.0-5.5 g/min in terms of pure silicon, and after deposition is completed, a deposition tube is melted and contracted to form a solid core rod on an electric hot melting and contracting bed. The deposition rate and the production efficiency of the PCVD process are effectively increased, the deposition rate and the processing quality are better balanced, and the core layer machining quality and accuracy are further improved.