Co2O3 doped (Ba0.85Ca0.15)(Ti0.92Zr0.08)O3(BCTZ-x%Co,x=0 ~ 1.4) lead free ceramics have been prepared by the solid state method. The influence of Co2O3 content on the microstructure, dielectric and piezoelectric properties were investigated. The results show that all the samples possess a pure perovskite phase structure. With increasing of Co2O3 content, the grain size decreased gradually, together with the decrease of the dielectric constant εr， piezoelectric coefficient d33 and electromechanical coupling factor kp. Mechanical quality factor Qm improved significantly. The ceramic withx=0.7 exhibits the optimum electrical properties,d33=392 pC/N,kp =46.0%,Qm = 435, tan δ=0.62%.The results show that the BCTZ-xCo ceramic is a promising candidate for lead free piezoelectric ceramics.