The new IGCP project “World Correlation of Karst Ecosystem” was approved early 2000 by the IGCP Scientific Board for implementation from 2000 to 2004. The objectives of the Project are:(1) to compare the karst ecological systems in tropical and subtropical, Mediterranean, Gondwana, arid and semiarid and other regions, their mechanism of formation, and differcnt impacts on human life; (2) to compare the microscopic karst ecological systecm as affected by different geochemical backgrounds and phases of carbonate rocks, especially their impacts on species selection and biodiversity, and thereafter the rehabilitation of karstlands; (3) to compare the subterranean ecological systems of karst on both geographical and geological views, and explore their differences on the evolution of troglobite, troglophile and trogloxene species and relation with surface species;(4)to compare the mutual effects of karst ecological system and human activities, e.g, the impact of karst ecological system on agriculture, forest, human health, and on the other hand, the impact of human activities(urbanization, timbering, mining, quarrying, agriculture, etc.) on karst ecosystem. During the 5 years time, in addition to investigating karst ecosystems of more than 40 participating countries, joint field correlation will take place in typical karst systems in Romania,Brazil, China,Spain,France, USA, Russia, and Australia to compare different karst ecosystems into depth. The key scientific issue of IGCP 448 is the running regularities of a karst ecosystem. A better understanding on such regularities is important for the comprehensive rehabilitation of rock desertified areas in SW China. On the bases of the experiences in China, the paper discusses the structure, driving forces and functions of a karst ecosystem, The differences of the researches in this direction betwecn China and other countries are analyzed. Suggestions on how to take the advantages of the implementation of IGCP 448 and carry out karst ecosystem study in China are put forward.