Cold sintering process (CSP) is an efficient and energy saving sintering method emerging in recent years. In this paper, the (1-x)BNT-xNN dielectric ceramics with the density of more than 97% were prepared by CSP. The effect of CSP parameters and NaNbO3 content on the density, phase structure, microstructure, and dielectric characteristics of (1-x)BNT-xNN ceramics were investigated. The results show that the CSP can drastically reduce the grain size and prevent some components like Bi and Na from volatilizing due to low sintering temperature and short holding time, thereby increasing the dielectric constant and reducing the dielectric loss. The remnant polarization decreases, and the temperature stability of dielectric constant increases as the content of NaNbO3 increases. When x=0.3, the variation in dielectric constant of the 0.7BNT-0.3NN ceramic is less than 6% at 25?傆b400 ℃, and the dielectric loss is less than 5%. It is indicated that the (1-x)BNT-xNN ceramics prepared by CSP are one of the promising candidates for the applications in temperature-stability ceramic capacitors.