Text retrieval systems require an index to allow fast access to documents at the cost of some storage overhead. This paper proposes a novel full-text indexing model for Chinese text retrieval based on the concept of adjacency matrix of directed graph. Using this indexing model, retrieval systems need to keep only indexing data, rather than indexing data and original text data as the traditional retrieval systems do, thus system space cost as a whole can be reduced drastically while retrieval efficiency is maintained satisfactory. Experiments over five real-world Chinese text collections are carried out to demonstrate the effectiveness and efficiency of this model.