Legionary theoretic problems of eco-environment in China West Arid Land, which are related with the multi-process of global change, local climatic instability and human disturbance, are typical for worldwide.

Eleven major humidity proxy records and other supplementary evidences including different natural archives such as ice-cores, sedimentary records, river terraces, lake-level fluctuations as well as historical documents are involved to reconstruct the humidity variability in the arid Northwest China during the Little Ice Age (LIA) from 1400 AD to 1920 AD.