In the present paper, spherical porous N-doped carbon nanomaterials were synthesized using polyaniline nanofiber as nitrogen-carbon precursor through spray drying and high temperature carbonation. In the process of spray drying, polyaniline fibers were entangled to form spherical nanomaterials with pore structures. The average diameter of the carbon spheres prepared by spray drying was about 3 mu m. After high temperature carbonation, the diameter shrunk to 2 mu m. The catalyst (CSDP-900) which was fabricated by spray drying and high temperature carbonation at 900 degrees C exhibited a high onset potential and a nearly four-electron pathway for oxygen reduction reaction (ORR) in 0.1M KOH solution as well as stronger methanol tolerance and better long-term durability than commercial Pt/C. This paper provides a novel, easy and scalable method to prepare N-doped porous carbon spheres with excellent ORR catalytic properties.