In this study, the effect of Mn $O_2$ additive on the electrical characteristics of PZN-PSS-PZT Pyroelectric materials for the fire detactor was studies. PZT ceramics used this experimental is 4 composite system $[$Pb(Z $n_{1}$3/ N $b_{2}$3/) $O_3$＋Pb(S $n_{1}$3/ S $b_{2}$3/) $O_3$＋PbTi $O_3$＋PbZr $O_3$$]$The dielectric constants and dissipation factors decreases as to Mn $O_2$ concentration increases. At the Mn $O_2$ 0.5($omega$t%), Pyroelectric coefficient shows 8(10$^{-8C}$$ extrm{cm}^2$$^{circ}C$) which have the highst value among other additive contents. It is found that output voltage shows maximum peck at Mn $O_2$0.7($omega$t％) is associated with the higher pyroelectric coefficient and Lowered dielectric constant.t.