The paper elaborates on the method for building cTAKES, a clinical text natural language processing system, from the three aspects of system architecture, building of corpus and application effect, and puts forward recommendations on the building of Chinese clinical text natural language processing system from the five aspects, including design of system architecture based on open source framework, development of modular components, building of clinical corpus, attention given to innovation and building of the system in the light of the feature of Chinese language.