Due to the explosive growth of the WWW and the increasing amount of data available via the Internet, how to retrieve desired information from the Internet with high efficiency and good effectiveness is of great importance. In this paper, we propose an information retrieval model for use in large dynamic networks such as the Internet. Firstly, we divide the network into a number of groups. An exceptional handling mechanism is adopted, i.e., a controlled flooding algorithm for intre-group information updating and random walk algorithm for inter-group information retrieval. We also propose an equal representative mechanism to enhance the fault-tolerant ability of the system. Extensive experiments are conducted to evaluate the performance and rationality of our model. The experimental results show that our model outperforms the existing approaches on the retrieval efficiency and the fault-tolerant ability.