Abstract: Based on multi-source remote sensing satellite data from spring (March to May) 2020, this study conducted a statistical analysis of the distribution characteristics, propagation directions, crest line lengths, and half-widths of internal solitary waves in the northeastern South China Sea. The results indicate that the crest lines of internal solitary waves generally exhibit a southeast-northwest orientation, with over 90% concentrated west of 118°E. Upon reaching the Dongsha Atoll, the waves undergo diffraction and reflection, forming a rarely observed northward-propagating internal solitary wave. Statistics on propagation directions show that incident waves primarily propagate westward or northwestward in deep-sea regions. Near the atoll, their propagation direction splits into a northwest (270°-330°) branch and a southwest (220°-260°) branch. In the diffraction process, the northern diffracted waves propagate northwestward (280°-320°), while parts of the southern diffracted waves initially deflect southwestward before turning northwestward. Ultimately, all propagation directions become perpendicular to the isobaths. Reflected waves mainly propagate eastward or northeastward (40°–130°), with a minority moving southeastward. Additionally, northward waves, interspersed among the northern diffracted waves, propagate northward or northeastward (0°-15°). Regarding crest line length, incident waves in deep-sea regions maintain a relatively stable length ranging from 90 to 150 km. In shallow waters, influenced by topography, some crest lines can extend up to 270 km. The northern diffracted waves have a crest line length of approximately 150 km, while the southern diffracted waves increase from 40 km to 125 km. Reflected waves grow from 30 km to 125 km before shortening to 80 km and disappearing. The crest line length of northward waves gradually increases from low to high latitudes, growing from 60 km to 130 km. Calculations of half-width reveal that the half-width of incident waves increases from 300-400 m to 950 m. The half-width of diffracted waves gradually narrows during propagation, with the northern branch decreasing from 950 m to 400 m and the southern branch from 1,100 m to 550 m. The half-width of reflected waves initially measures 550-700 m and increases to 980 m during eastward propagation, showing an overall gradually increasing trend. The half-width of northward waves first decreases from 770 m to 250 m within 21°00′-21°24′N, then increases to 750 m. The analysis suggests that half-width is significantly modulated by topography and nonlinear effects. Topography directly influences half-width by controlling the vertical modal structure, resulting in narrower half-widths for internal solitary waves in shallow continental slope areas compared to deep-water regions. Enhanced nonlinear effects lead to the contraction of the half-width of internal solitary waves.