Abstract: As a site of Globally Important Agricultural Heritage Systems (GIAHS) and a World Cultural Heritage, there is rich biodiversity in Yunnan′s Honghe Hani terraced paddy rice fields with important ecological, economic and social values. Resource plants refer to the plants that are beneficial and available to human beings, often carrying rich traditional knowledge of collection, utilization and management of plants, and showing the reciprocal relationship between man and plants. The Hani terraced ecosystem is composed of forests, villages, terraced rice paddies and water systems in Honghe Hani and Yi Autonomous Prefecture, Yunnan, Southwest China. Plants, in particular useful plants, as the crucial component of this ecosystem for maintaining its stability, unfortunately, has always been overlooked. Through the methods of plant taxonomy, plant ecology and ethnobotany, the present study revealed the status of major resource plant diversity and associated traditional knowledge of the Hani terraced ecosystem. The sampling areas covered the paddy rice fields together with their surrounding forest lands from four counties with most Hani terraces in Honghe Prefecture. The relationship between the Hani terraced rice ecosystem and plant diversity has been analyzed. The results show that there are 651 species of useful plants in the Hani terraced ecosystem, including 255 medicinal plant species and 226 edible plant species. The local people have rich traditional knowledge in the management and utilization of these plants, such as the scared forests and trees, edible and medicinal plants, cultivation of Amomum tsaoko and Strobilanthes cusia, and firewood collection. The plants can be used for daily production, livelihood and protection of Hani terraced paddy rice fields with obvious characteristics of the resources of multi-purposes and multi-functions, indicating the profound plant utilization culture and the close human-land interaction on which the stability of agricultural heritage will depend. The local rich plant diversity formed the basis of Hani terraced rice field ecosystem. The long-term collection, management and use of plant resources reflected traditional knowledge and culture, and supported local people′s livelihood. The rich plant diversity, combined with its traditional knowledge, plays a very important role in maintaining the entire Hani terraced agroecosystem, conserving agricultural heritage and promoting rural economy.