Leaf is one of the most sensitive organs that response to atmospheric environment changes. In arid region, especially under water stress conditions, water from foliar uptake is one of the main water subsidy sources, which plays an important role in plant survival, growth and ecosystem sustainable development. Foliar water uptake attracts more attention in physiological and ecological research all over the world. This essay summarized the main measurement methods of foliar water uptake at home and abroad in detail: vessel control method, stable isotope technology and heat ratio method. And analyzed the significance of foliar water uptake from physiological and ecological aspects; and discussed the influence factors of foliar water uptake from water condition perspective, water absorption and leaf structure aspects. The following aspects should be paid more attention in future researches: (1) measure the amount of foliar water uptake by using stable isotope technology and heat ratio method; (2) the relationship among foliar uptake of fog, dew, rain and water vapor in arid region; (3) the foliar uptake amount and rate should be simulated by models; (4) the mechanisms of foliar water uptake should be researched; (5) study foliar water uptake of different plants at ecosystem scale.