The natural environmental condition, such as precipitation, air temperature, humidity and radiation, varies continuously with a wide spectrum of temporal scales from seconds to years and decades. Such variations are subject to slow and fast changes of solar radiation, passages of a front and pressure systems, and frequency of precipitation. In the Asian region, the monsoon system is driving temporal variability in the natural environment and consequently it makes impact on carbon and water cycles on from local, regional to continental and global scales. Terrestrial ecosystems in Asia cover wide spectrum of biomes and climate zones and represent many vegetation types. In particular, due to rapid changes of land cover and large population pressure for economic growth, the carbon and water cycles of the terrestrial ecosystems in Asia have undergone dramatic changes over the past several decades, leading to potentially significant influences on global climate change. Under future global warming scenario, seasonal precipitation cycle can be amplified in the Asian region. There is, however, the lack of our understanding on the interplay between the Asian monsoon and terrestrial carbon and water exchanges that hinders us from better understanding of carbon and water cycles and its impact on climate change. Using the ecosystem models, my presentation will briefly discuss major challenges in modeling ecosystem carbon and water exchanges in Monsoon Asia and their interplay with the Asian monsoon.