AgSbTe2 has great potential for power generation applications from low to medium temperatures because of its inherent low thermal conductivity with a large Seebeck coefficient. However, the electrical properties of the AgSbTe2 system have not been effectively improved due to the intrinsically low carrier concentration and the disorder of the cations, which are physically coupled and lead to the low charge mobility of the material. In this work, a series of AgSb0.96 Q0.04 Te2 (Q=Ge, Zn, Cd, Sn, Pb) thermoelectric compounds were prepared by doping divalent elements into Sb ion sites, successfully achieving decoupling between the carrier concentration and carrier mobility, thereby greatly improving the thermoelectric performance of AgSbTe2 . The results show that doping with Pb can optimize the carrier concentration of p-type AgSbTe2 without decreasing carrier mobility, thereby greatly improving the electrical performance. The maximum conductivity and power factor for AgSb0.96 Pb0.04 Te2 reach 229 S/cm and 15.1 μW/(cm·K2) at 548 K, respectively, which are 108% and 44% greater than those of the intrinsic sample. The resulting zT value of the AgSb0.96 Pb0.04 Te2 crystal reaches 0.60 (298 K) and 1.53 (548 K), contributing a high average zT of ~1.10 from 298 K to 598 K.