Bulk FexCo4-xSb12 with x varies from 0.1 to 2.0 were prepared by mechanical milling (MM) and spark plasma sintering (SPS). The phases of the products were characterized by X-ray diffraction (XRD) and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of bulk FexCo4-xSb12 are skutterudite. The electrical resistivities of the products increase first and then decrease. The Seebeck coefficients ( ) are negative when x=0.1 at 100 °C and 200 °C while positive at 300~500 °C. The products with x=0.5~2.0 at 100~500 °C are P type semiconducting materials due to their positive values. The thermal conductivities of most samples increase first and then decrease with x increasing and the maximum is up to 0.39 Wm-1K-1 when x=1.0. The ZT values at 200~500 °C increase first and then decrease with x increasing when x=0.1~1.0 and x=1.0~2.0 respectively and the maximum ZT value is 0.196 when x=1.5 at 400 °C.