(Pb,La,Sr)(Zr,Sn,Ti,Nb)O3 + xmol% MnO2 (PLSZSTNM) ceramics with broad working temperature are fabricated by a wet-chemistry method. The effects of Mn-doping on dielectric breakdown strength, morphology, temperature-stability and dielectric properties have been investigated in detail. The ferroelectric behavior of PLSZSTNM ceramics is strongly affected by Mn doping. With increasing Mn-doping, dielectric constant of ceramics increase, followed by a drop. Furthermore, as the Mn amount is 0.2 mol%, the dielectric loss of capacitance is below 0.01 and the dielectric constant of the composites is about 577.5. The temperature coefficient of capacity varied from − 14.9 to 8.3% at the temperature range between − 55 and 200 °C. The temperature–capacitance characteristics of PLSZSTNM ceramics meet EIA X9R specifications, which lays a foundation for high temperature-stable materials.