In the present work, a series of single phase Fe-/Ni- double doped skutterudite compounds Co3.8-xFexNi0.2Sb12 (x=0.05, 0.1, 0.15, 0.2) were successful synthesized by 5 min microwave heating for the first time. The resulting ingots was pulverized and sintered by spark plasma sintering to fabricate bulk samples, and their phase composition, grain size, element distribution, thermoelectric transport properties have been investigated systematically. The XRD patterns show that all samples are consistent with single phase of CoSb3. The FE-SEM morphologies reveal that the size of Co3.8-xFexNi0.2Sb12 matrix grain are about 1~3 μm, the average size are about 1~2 μm. The EDS elemental maps revealing uniform Co, Fe, Ni, and Sb distributions. The electrical transport properties were further improved by Ni/Fe double doping, resulting a highest power factor of 2.667×103 μWm?1K?2. The influence of Fe doping on lattice thermal conductivity is not so significant, but there is a relationship between lattice thermal conductivity and grain size, and boundary scattering is most likely to be the dominant scattering mechanism. The lattice thermal conductivity of Co3.65Fe0.15Ni0.2Sb12 is 2.8Wm-1K-1. The Co3.7Fe0.1Ni0.2Sb12 has the highest ZT of 0.50 at 773 K, which are obviously larger than those of Ni- /Fe- single or double doped samples produced via traditional techniques.