In this work, we successfully prepared gold nanoparticles (AuNPs) within a germanium-tin-sulfur (Ge-Sn-S, GSS) chalcogenide glass (ChG). The formation of AuNPs in the GSS ChG relies on the reduction capacity of Sn(2+)ions, which we found their existence in the glass matrix by the characteristic emissions at nearly 450 nm. The AuNPs exhibit strong optical activity which caused a significant enhancement of third-order optical nonlinearity of the GSS ChG as well as photon luminescence of the Sn(2+)ions. In addition, optical properties the AuNPs-embedded GSS ChGs can be modified by further gold doping and one-step heat-treatment process.