Without any other additives or additional energy, gold quasi microspheres with novel hierarchical structure have been successfully prepared and integrated simultaneously with a conducting polyaniline/polyacrylonitrile blend film via the in situ reduction of AuCl4- on the film surface. The morphology and structure of the as-prepared gold microspheres are characterized, and its application as catalyst is also investigated. By controlling the concentration of HAuCl4 and polyaniline content (or conductivity) of polyaniline/polyacrylonitrile blend films, the amount and size of gold microspheres can be effectively adjusted. It is suggested that the polyaniline chains of the blend films play both reducing and structure-directing roles during the formation of Au microspheres with hierarchical structure. The catalytic studies show that the hierarchical gold microspheres give highly catalytic activity when taking the reduction of p-nitrophenol as a mode reaction. (C) 2010 Elsevier B.V. All rights reserved.