The invention discloses polythiophene microballs and a preparation method thereof and provides a method for preparing conductive polymer polythiophene microballs at one step by chemical oxidation polymerizing method. The method includes firstly, providing a diffusion system containing thiophene monomer and inorganic precursor; secondly, polymerizing the thiophene in the diffusion system to be polythiophene, and forming polythiophene microballs; and thirdly, separating the polythiophene microballs from the diffusion system. By regulating solvent, thiophene motor and oxidant and proportions thereof in the diffusion system, controllable synthesis of the polythiophene microballs different in shape and size can be realized. The preparation method is simple, environment-friendly in process and low in cost, and the polythiophene microballs prepared by the preparation method are uniform in size.