Scientific forecasting of living environment change for the human society requires a proper understanding of the mechanism and the nature of climate-environment changes. Recent progresses in the studies of tropical process and atmospheric CO₂ concentration further reveal the imperfection of the classical Milankovitch theory on the role of low latitude region and carbon cycle in the global climate system, although it has been widely applied to orbitaldriven glacial cycles. The new National Key Basic Research Science Foundation (973) project, entitled "Ocean Carbon Cycle and Tropical Forcing of Climate Evolution", is aimed to clarify and test the hypothesis about the long period of ocean carbon reservoir. This project will achieve global correlation and probe into the connection between different earth's spheres, based on the the deep sea records of the South China Sea and western Pacific warm pool. The results of observations will be combined with mathematic modeling to reveal the role of low latitude process in the global climate environment through carbon cycling on various time scales, contributing to international studies of the evolution of the climate system. This article briefly introduces the research purpose, science siginificance, key sciencfic questions and expected goals of the project.