This paper investigated the effects of nano-silicon carbide (SiC) powder on the thermoelectric properties of both fly ash and metakaolin based geopolymer. The influences of different parameters, i.e., SiC dosage, alkali concentration and curing temperature, were investigated. Results showed that the addition of SiC powder effectively increased the Seebeck coefficient of geopolymers because of the quantum confinement effect. A higher alkali concentration is capable of increasing the Seebeck coefficient of both fly ash and metakaolin based geopolymer, while curing temperature has an insignificant influence on the Seebeck effect of metakaolin based geopolymer.