With the financial supports of Ministry of Science and Technology, NEEC has successfully researched and developed “the co-phase power supply device for electrified railway” which is the first set of prototype in the world. It is granted by 42.15 million yuan with state funds of 12.18 million yuan,The prototype has passed the inspection and acceptance of the Ministry of Science and Technology and has been highly evaluated by specialists. The achievements show that it is not necessary to set up neutral sectioning devices or decease neutral sectioning devices that it also eliminates the effect of the negative sequence and give consideration to both reactive power compensation and harmonic filtration. Also It has obtained 4 authorizations/patents and published 36 papers.This prototype is pushing forward the early stage of the trial work of heavy haul South-central railway. The achievements have totally changed power supply modes of traction power supply system and will make a significant impact on technological progress of the industry.