The preservation of shale gas is identified as a key factor in the breakthrough of marine shale gas exploration in southern China. The Nanpanjiang Basin holds tremendous exploration potential, with the Luzhai Formation in the Langdai area serving as the primary stratum for shale gas occurrence. This formation predominantly consists of deep-water platform facies mud shale, siliceous rock, and silty siliceous rock. The organic matter is classified as Type II1 and II2, with a total organic carbon (TOC) content ranging from 2.0% to 3.0%, and a thermal maturity (Ro) between 2.0% and 2.5%. In this study, an analysis of the shale gas preservation conditions in the Luzhai Formation of the Langdai area was conducted by employing a variety of methods, including field section measurement, field fracture statistics, scanning electron microscopy, organic geochemical testing, breakthrough pressure testing, and fluid inclusion identification. The evaluation parameters were superimposed using a weighting coefficient, and the mean clustering analysis method was applied. An evaluation index for preservation conditions was established based on six categories of influencing factors: shale burial depth, shale thickness, sealing conditions, structural morphology, fracture development characteristics, and fissure development characteristics. Three categories of favorable areas for shale gas preservation were delineated, effectively reflecting the degree of influence of different parameters on preservation conditions, thus making the evaluation results more accurate and reliable. The Class I favorable area is located at the core of the Xinzhai anticline, where the material foundation for burial depth and sealing conditions is superior, with favorable morphology and relatively weak fracture influence. The Class II favorable area is situated at the Xinzhai anticline and the northern region of the Qinglong anticline, where the shale system's material foundation is average due to the influence of stratum dip angle and burial depth. Surrounding the Langdai anticline and the Class II preservation area of the Qinglong anticline lies the Class III favorable area, where structural damage is more pronounced, adversely affecting the preservation of shale gas.