Si3N4 Ceramic Composites with TiC powder have been fabricated by gas-pressure sintering and their electrical conductivity has been investigated. The ceramic composites with different electrical resistivity consist of Si3N4 powder as an insulating matrix, and TiC as electrically conductive additive. Under tensile loading or compressive unloading, the Delta R/R of TiC/Si3N4 composites reversibly increased. Under compressive loading, the Delta R/R decreased gradually with the increasing of loading up to fracture. The results suggest the possibility of self-monitoring fractures and strains in the composites under tensile and compressive loading.