The South China Sea (SCS) is a region where internal solitary waves (ISWs) are very active. The ISWs will propagate westward after they form in the northern SCS. During the propagation process of the ISWs past the DongSha Island, their shapes and amplitudes will change accordingly. This paper mainly investigates the three-dimensional evolution characteristics of the ISWs past an Island by use of the experimental method. In this experiment, an ISW propagates in a two-layer fluid with the pure water in the upper and the salt water of constant density in the lower. The waveform changes of the ISW induced by the Island are observed by the fluorescent method and are qualitatively compared with the surface signature of ISWs captured by Synthetic Aperture Radar (SAR), as well as the amplitude variations of the ISW in different locations are successfully inversed by using the fluorescent method combined with the dyeing technique after its passes the island. Further experimental results from the combination of the fluorescent and dyeing method suggest that it is possible to obtain the quantitative analysis results combining the fluorescent and dyeing method.