This article intends to demonstrate the principles for dictionary compilation. To summarize, general rules are to be fol-lowed. At the same time ,this article probes into the differences of Chinese to Chinese dictionary, Chinese to foreign language dictionary, dictionaries for the preparation of certain exams, learner's dictionaries for reviewing errors, dictionaries with multi-media and dictionaries built via the Internet.. In all, one of the key factors for dictionary compilation is the professionalism of ed-itors and writers. The training of the people involved is vital, which would contribute to setting up a better order of the market. Acknowledgements should also be given to achievements in dictionary compilation. Revisions and polishing are required to im-prove the dictionaries on the market that have already won the acclaim so as to put their influence to the best display.