Flexible flowline is an important part of offshore oil and gas development， and its offshore installation is the core ability and key technology of offshore engineering companies. Based on China's first self-developed 1500m ultra-deep water Lingshui 17-2 gas field， and the domestic first 3000m-class deep-water MSV “Hai yang Shi You 286”， the installation feasibility of 1500m water depth flexible flowline by vertical-lay method for “HYSY 286” is evaluated. The key technology and solution of vertical-lay of ultra-deep water flexible flowline are studied. Through the engineering application in Lingshui 17-2 gas field， the feasibility of the relevant technology is verified， and the gap in domestic technology field is filled， and the technical reserve and experience are provided for the installation of deep water flexible flowline in the future.