The present invention relates to carbon nanotube fibers reinforced with a carbon precursor and a method for manufacturing the same. The carbon nanotube fibers reinforced with a carbon precursor according to the present invention are carbonized by the empty space inside the carbon nanotube fibers being filled with a carbon precursor, and therefore, are highly effective in that the mechanical and thermal properties are improved due to effective stress transfer and contact resistance decrease, and these properties are maintained intact even at high temperatures.