Abstract: Most species of the genus Cassytha are confined in Australia, and a few species are found in Africa. However, Cassytha filiformis L. is a particular species is distributed all over the world in a pan-tropical manner. The purpose of this study is to simulate the potential suitable areas of this widely distributed species (C. filiformis) and narrow-range species, analyze the environmental differences of their suitable areas, and analyze the distribution pattern of the genus Cassytha diversity and the underlying causes, in order to provide basic information for the protection of forest diversity and the stability of ecological environment. The results showed that, based on environmental variables, the MaxEnt model had a high accuracy in predicting the potential distribution areas of the genus Cassytha. The area under the receiver operating characteristic curve (AUC value) was greater than 0.9 for both the training and test sets, indicating a good confidence in the predictions. Based on the contribution rate of environmental variables and the Jackknife method, the results showed that precipitation, temperature, and soil were the main factors limiting the distribution of the genus Cassytha species. The distribution of most narrow species were greatly affected by soil conditions, while the distribution of C. filiformis was not significantly limited by soil factors. Overall, the environmental factors affected the geographical distribution of the genus Cassytha species had suitable thresholds and narrow ranges, except for C. filiformis, which had the largest range of thresholds. It is currently tentatively hypothesized that the wide distribution of C. filiformis and the narrow distribution of the other species can be attributed to four reasons. Firstly, C. filiformis has strong environmental adaptability, and can tolerate a wide range of dominant factors that influence its distribution. Secondly, the distribution of this species is not limited by soil factors. Thirdly, the seeds of the C. filiformis can diffuse over a long distance. Lastly, this species has the ability to utilize a wide variety of hosts for its survival and reproduction.