Design diagram of the third-generation ballistic missile nuclear submarine for the French Navy. According to foreign media reports, the French Navy recently held a steel plate cutting ceremony for the first ship of the third-generation ballistic missile nuclear submarine at the Cherbourg Shipyard, marking the official start of construction for this class of submarine. The French Navy stated that the third-generation ballistic missile nuclear submarine, as a replacement for the active Triumph class ballistic missile nuclear submarine, began planning in 2012 and was approved in 2017. It is expected to deliver the first ship after 2035, and will be built every 5 years, with a total of 4 ships built thereafter. From planning and design to full delivery and use, France has spent nearly 30 years building a new generation of strategic nuclear submarines. What are the characteristics of the design of this class of boats? Where will the development of the new generation of strategic nuclear submarines go? This article provides an interpretation of this. France has been adhering to a limited nuclear deterrence strategy for a long time, continuing its maritime nuclear deterrence. Since the early 1970s, France has maintained at least one ballistic missile nuclear submarine in an underwater combat readiness cruising state since its first strategic nuclear submarine, HMS Dreadnought, carried out its first nuclear missile cruise mission. In 1998, after abandoning land-based nuclear weapons, France focused on developing strategic nuclear forces in the sea and air. Among them, sea-based nuclear forces have become the focus of the construction of France's nuclear power system due to their strong concealment and good destructive effects. The number of nuclear warheads owned by the French sea-based nuclear force accounts for about 80% of its total number of nuclear warheads. At present, the French Navy has four Triumph class ballistic missile nuclear submarines in service. By 2035, among these four strategic nuclear submarines, even the latest built No. 4 submarine will have a service life of over 25 years, facing problems such as outdated technology and outdated equipment. To this end, the French Navy plans to use four third-generation ballistic missile nuclear submarines to replace the Triumph class ballistic missile nuclear submarines one-on-one, ensuring the continuity of France's maritime strategic nuclear deterrence and nuclear counterattack capabilities. According to public information from the French Navy Group, the hull design and combat performance of the third-generation ballistic missile nuclear submarine in France are improved on the basis of the Triumph class ballistic missile nuclear submarine, with a focus on enhancing and developing stealth, mobility, and automation. According to public information, the third-generation ballistic missile nuclear submarine in France is approximately 150 meters long and has a full displacement of 15000 tons. After completion, it will be the largest strategic nuclear submarine in France. The enlarged hull not only facilitates the installation of the new generation nuclear reactor system, but also meets the requirements for carrying the improved M-51 intercontinental ballistic missile, and provides ample space for the bow to be equipped with a large array sonar. In addition, the level of automation and intelligence of this type of boat is relatively high. For example, equip an intelligent combat management system that can quickly process a large amount of sensor information. Thanks to its high level of automation, the number of crew members is only 100. The third-generation ballistic missile nuclear submarine in France is equipped with 16 vertical missile launchers, which will be equipped with the latest model of the M-51 intercontinental ballistic missile. It has the characteristics of strong penetration, long range, and high hit accuracy. Compared with the previous generation model, this missile carries more nuclear warheads, higher intelligence, and stronger destructive effects. In addition, the bow of the third-generation ballistic missile nuclear submarine is equipped with four heavy torpedo launch tubes, which can launch F-21 heavy torpedoes, next-generation anti-ship missiles, and can also launch unmanned aerial vehicles