Objective To discuss the concept of ulnar tunnel at thewrist, the types, causes, traits of compression, diagnosis, and clinical significance of ulnar tunnel syndrome(UTS). Methods Thirty-nine cases diagnosed as having UTS from 1986 were retrospectively reviewed combined with previous relevant literature. Results Ulnar tunnel included Guyon’s canal, pisohamate tunnel and hypothenar segment. There were 8 types andmany causes of UTS. Some patients had compression in more than one zones and might be associated with carpal tunnel syndrome or cubital tunnel syndrome. UTS could be diagnosed through clinical manifestations and electrophysiological examination. Conclusion Defining the concept of ulnar tunnel and the knowledge of the complexity and rarity of UTS can effectively guide diagnosis and treatment.