The launch of a medium-sized cruise ship is a vital part of the cruise ship construction process, especially as the large inclination angle during the launch is critical for stability, so this paper assesses the safety of the stability of the launch of a medium-sized cruise ship based on Maxsurf. The static stability calculation module in Maxsurf is used to carry out a complete stability analysis of the dockyard's launch scenario; using a 52,000 gross tonne Viking cruise liner as an example, its hydrostatic curve is plotted and its stability is checked for large inclination angles under the loading conditions of the launch, according to the class and specifications entered. The results show that the stability of the launch of a medium-sized cruise ship meets all the requirements of the code and can ensure its safety in the water. It also proves the reliability of using Maxsurf to calculate and analyse the stability of the launch of a medium-sized cruise ship. The stability calculations based on Maxsurf before the launch of a medium-sized cruise ship can be used as a reference for the stability calculations and analysis of the launch plan of a medium-sized cruise ship later on, and can also be used directly as a manual for stability calculations before the launch of a medium-sized cruise ship and as information for the classification society.