Sentence processing involves the integration of different linguistic information, such as phonetic, lexical, syntactic, semantic information. Researchers proposed three kinds of theoretical models: sectional model, parallel model, and unified model. The argument focuses on the time course and the interaction among linguistic information. From the recent experimental results, we infer that: 1) In sentence processing, syntactic information probably acts backward while semantic information probably acts forward. 2) The strength of linguistic information in processing sentence is probably determined by its own linguistic level. However, which level is stronger / weaker remains unclear. More experiments on pragmatic information processing need to be made. Chinese linguistic information integration needs to be further discussed separately from Indo European language processing.