Rare earth ceramics, La 0 67 Ba 0 33 Mn 1- x Fe x O 3( x =0,0 05,0 1), has been prepared. The saturation magnetization and Curie temperature decrease with increasing Fe content in the compounds La 0 67 Ba 0 33 Mn 1- x Fe x O 3,since Fe does not participate in double exchange interaction and the amount of bond Mn 3+ O 2 Mn 4+ decreases. The ferromagnetic interaction decreases with Fe doping in the compounds La 0 67 Ba 0 33 Mn 1 x Fe x O 3. Fe doping also dereases the transition temperature of the metal semiconductor transition peak and increases the resistance of La 0 67 Ba 0 33 Mn 1 x Fe x O 3. The colossal magneloresistance(CMR) effect at low temperatures has been improved for doped La 0 67 Ba 0 33 Mn 1 x Fe x O 3. The magnetoresistance ratio [ R (6T) R (0)]/ R (0) changes from 40% to 60% with increasing Fe content from x=0 to x=0 1 . The results also show that the metal semiconductor transition peak and the negative CMR effect are well described by the Dionne model.