The Lingshui 17-2 deepwater gas field semi-submersible platform is the worlds first 100 000-ton class deepwater semi-submersible production and storage platform. In view of its characteristics such as high natural gas pressure, large gas flow rate, low flash point of condensate and strict weight control, a series of safeguarding measures applicable to the deepwater semi-submersible production and storage platform are proposed. These innovative design features include the application of SSIV(subsea isolation valve), HIPPS(high-integrity pressure protection system), and condensate tank inert gas blanketing system. Detailed discussions and verifications on aspects such as the necessity of safeguarding systems, their locations and special design features are also carried out to ensure the safe operation of the deepwater semi-submersible production and storage platform, which provides valuable reference for the development of large deepwater gas fields in the future.