Abstract: La-doped Ca manganese oxide powders ((La_{1- x} Ca_x Mn_{0. 7}Co_{0. 3}O₃, x = 1. 0, 0. 9, 0. 8 , 0. 7, 0.6) and their polypyrrole compositesLa_{0. 3}Ca_0.7Mn_{0. 7}Co_{0. 3}O₃/PPy with 60 % and 80 % PPy were prepared by a glycine-nit rate combustion method and an as-polymerization method, respectively. The structure, morphologies and electrochemical properties of the samples were characterized by means of Fourier transform inf rared (FTIR) spectrometer, powder X-ray diff ractometer (XRD), scanning electron microscope (SEM) and electrochemical tests. The results indicate that interactions exist between polypyrrole and complex oxide. Furthermore, PPy reduces the reunion of the nano2particles, i. e. the particle sizes ofLa_{0. 3}Ca_0.7Mn_{0. 7}Co_{0. 3}O₃ andLa_{0. 3}Ca_0.7Mn_{0. 7}Co_{0. 3}O₃/PPy are 46. 2 nm and 43. 5 nm, respectively. The composite redox peak current becomes larger with increasing of pyrrole contents.