A method for producing vapor-grown carbon fibers (VGCF) having a three-dimensional linkage structure is disclosed. The method includes directly delivering heterogeneous catalysts dissolved in a liquid hydrocarbon raw material into a reaction chamber so as to continuously grow vapor-grown carbon fibers having a three-dimensional linkage structure without additional treatment. The method adopts a fluidized bed method, wherein a raw material solution consisting of a hydrocarbon compound, ferrocene (Fe(C.sub.5H.sub.5).sub.2), thiophene and an organometalic (non-iron) compound is vaporized by preheat. Thereafter, the raw material gas and hydrogen gas are injected into a tubular reactor and pyrolized to produce vapor-grown carbon fibers with 3-D linkage structure.