Effects of preparation technology on structure and thermoelectric properties of NixCo4-xSb12(x=0.1~0.5)were investigated separately by solid reaction-spark plasma sintering(SR-SPS)and mechanical milling-spark plasma sintering(MG-SPS)method.The two methods had little effect on phase structure and Seebeck coefficient,but SR-SPS technology augments electrical resistivity and the grain size of products when the content of Ni was as low as 0.1,and hence increase the thermal conductivity and decrease the thermoelectric properties.Compared with SR-SPS,MG-SPS method not only is simple and convenient in preparation,but also is propitious to the improvement the thermoelectric properties.In our experimental range,the Ni0.2Co3.8Sb12 bulk sintered by MG-SPS shows maximum ZT value of 0.6 at about 773 K.