The electrochemical detection of hydrogen peroxide in alkaline solution was performed on a La0.7Sr0.3Mn0.75Co0.25O3 (LSMCO) nanofiber modified carbon paste electrode. Perovskite-type oxide LSMCO nanofibers were prepared by electrospinning and calcination. The morphologies, structures, and electrochemical behaviours of the nanofibers were characterized by scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction and cyclic voltammetry. The modified electrode shows excellent electrocatalytic activity towards hydrogen peroxide. Under optimal conditions, the linear response was obtained in the range of 0.5-1000 mu M, with high sensitivity and a low limit of detection.