. The self-developed Φ-OTDR system was used to demonstrate and verify in an offshore wind farm in Fujian Province. The state analysis and diagnosis of Marine blower unit under different working conditions such as start-up， operation and shutdown were realized， and the vibration characteristics and diagnosis basis under different working conditions were summarized. In addition， according to the monitoring and warning functions of submarine cable， such as current impact， anchor damage towing， sailing of approaching ships， etc.， the characteristics of target event perception under different state of submarine cable and surrounding environment were summarized. The measured results showed that the scheme could monitor the status of sea blower and submarine cable online， and effectively perceive the surrounding environment， which could provide a reliable technical way to improve the operation and maintenance level of offshore wind farms.