Abstract:By investigation and statistics, we found that there were 18 Chinese endemic genera of seed plants in Jiangsu, containing 19 species, which belonged to 17 families. The percentages of the same group possessing in Jiangsu of China were: 19.32% of 88 families, 5.61% of 321 genera, and 2.53% of 751 species. According to its natural geographical features, we divided Jiangsu Province into six regions: Huanghuai Plain, Jianghuai Plain, Binhai Plain, Changjiang Delta, Northern low Massif and Southwest low Massif. It was for the first time that endemic index (EI) was applied to reveal the distribution pattern of the endemic genera in the regions. The result showed that the highest EI among six regions was 4.83, which appeared in Southwest low Massif; the second one was 3.89, which appeared in Changjiang Delta; the lowest one was 1.67, which appeared in Huanghuai Plain or Binhai Plain. The characteristics of Chinese endemic genera of seed plants in Jiangsu were as follows：（1）The floristic composition was relatively poor；（2）The geographical distribution was fairly uneven；（3）Most of these 18 genera, with different life forms, were palaeoendemic genera.