The present invention is related to a high loading supported carbon catalyst having Pt or a Pt alloy supported into an electrically conductive carbon support. Specifically, in the carbon supported catalyst, a loading of the supported Pt or Pt alloy is in the range of about 50% to about 60% by weight, an average particle size is about 1 nm to about 3 nm, and a total specific surface area of the carbon supported catalyst is greater than about 200 m.sup.2/g. The carbon supported catalyst may improve the performance of a fuel cell because the catalytic metal particles have a small size and a high degree of dispersion. Also, a carbon supported catalyst having very fine catalyst particles uniformly dispersed may be prepared even at a high loading may be prepared.