【目的】了解海南石灰岩地区种子植物区系组成、性质等基本特征.【方法】野外实地调查、标本采集与鉴定，数据统计分析.【结果和结论】海南石灰岩地区现共记录种子植物1 176种58变种1变型，隶属于142科645属，其中裸子植物5科5属7种，被子植物137科640属1 169种58变种1变型.具有明显的热带性质，以热带、亚热带成分尤其是热带亚洲成分为主，热带、亚热带成分分别占总科数和总属数的73.24%和87.75%；温带成分在海南石灰岩地区得到一定的发展，温带性质科占总科数的11.97%，属占总属数的7.29%.该地区物种丰富，以占不到全岛2％的面积，分布高达27.26％的种类，但属内种类较为贫乏，以单种科和寡种科为主，共计113科，占总科数的79.58%；中国特有属有2属.
【Objective】The purpose of this study was to reveal the floristic composition and characteristics of seed plants in limestone areas in Hainan.【Method】Extensive field work, specimens collection and identification were conducted to collect data for the analysis.【Result and conclusion】A total of 1 176 species, 58 varieties and 1 forma belonging to 645 genera and 142 families were recorded. The tropical and subtropical distribution elements, especially tropical Asia ones, were dominant in the limestone flora in Hainan. The tropical and subtropical distribution families accounted for 73.24% of the total and the genera accounted for 87.75%. The proportions of temperate distribution families and genera accounted for 11.97% and 7.29%, respectively. The limestone areas contributed about 27.26% to the total number of species with less than 2% land area of the whole island. However, many genera include only one or very few species. There are 113 single and few species families, accounting for 79.58% of the total families. There are 2 genera endemic to China.