Abstract: By the Licor--6400 portable photosynthesis system, a field study on the photosynthetic characteristics in leaves of Caragana during different period was determined. The main results were as follows= the light compensation points (LCP) in leaves of Caragana plantation changed from 37.4 to 70.92 lamol/(m2· s) in different periods, the light satura tion points(LSP) varied from 1 324.07 to 1 626.04/amol/(m2· s) and the apparent photon u tilization efficiency varied from 0.00899 to 0.01476μ mol/mol. The CO2 compensation point (CCP) of photosynthesis varied from 56.76 to 126.80 l, mol/mol. The CO2 saturation points (CSP) varied from 1154.60 to 1828.86μ mol/mol. It is C3 plant that can’t shade tolerance. So it has to be planted on sunny fields. TheTrofCaragana plantation during different periods shows TrSept>TrAug>TrJun>TrJul.>TryMay; the WUE shows WUeMay>WUEJul>WUEAug>WUEJun.>WUEsept.