SiC powders with nickel powders and sintering aids were prepared by pressureless sintering at 1500oC under a N2 atmosphere. XRD, TEM, SEM techniques were used to characterize the phases and microstructure of the specimens. The thermoelectric properties of SiC matrix composites were investigated by measuring the Seebeck coefficient and the electrical conductivity. The main phase of all samples was -SiC, the Ni2Si can be observed with adding nickel powders. The largest electric conductivity was close to 3.5 m-1-1 at about 973K. The highest Seeback coefficient was up to 1800 V/K at 1073K. The transition from n-type to p-type was occurred.