BaFe12O19 and La-Mn substituted M-type Ba hexaferrites were synthesized by sol-gel method and characterized by XRD, SEM and FTIR. The results showed that citric acid played an important role in the forming process of BaFe12O19. BaFe12O19, synthesized under lower citric acid and presintered at 450°C, showed improved hexagonal crystal phase. BaLa0.5Fe11.5O19 and Ba(MnLa)0.5Fe11O19 showed similar crystal structure to BaFe12O19 while Ba0.5Mn0.5Fe12O19 and Ba0.5Mn0.5La0.5Fe11.5O19 showed changed crystal constant. FTIR analysis proved the formation of new mental-oxygen bond in substituted hexaferrites.