As an important source for discovering new competitive technological intelligence involved in enterprises, patents can be analyzed to identify the technological strategy and the potential competitors. Based on the patent citation information, the weighted and directed enterprise citation network is established. Based on the modified PageRank algorithm, a novel method is provided to evaluate the technological influence power of enterprises. Experiments with this method have been done using the patent dataset in the field of fluid-pressure and analogous brake systems during the 25-year period from 1975 to 1999 from the United States Patent and Trademark Office. Compared with the traditional assessment indicator based on the citation count method, the proposed method is more reasonable in identifying the technological influential enterprises, as it gives a comprehensive consideration of the amount of citing enterprises, the influence of citing enterprises and the citation strength between them. This study helps enterprises discover potential technological competitors, which take the lead in the industry.