An advanced way for controlling desert and sandstorm to protect, recover and expand wetland in north and northwest China is proposed in this paper. The necessary conditions for increasing precipitation in inner continental basin contain mainly three aspects ： westerlies, high mountains for condensation and broad wetland fog as vapour resources . A scheme of project is envisaged, which introduces sea water from Bohai Sea through north Inner Mengolia to Xinjiang. The target of the project is to recover and expand wetland in northwest China. It will produce economis and ecological benefits in the aspects.