Abstract: With the aid of the Licor-6400 portable photosynthesis system,a field study on the photosynthetic characteristics in leaves of oriental oak forest during different seasons was determined.The main results were as follows:The light compensation points(LCP) in leaves of oriental oak changed from 40 to 42.21?μmol/(m~2·s) in different seasons,the light saturation points(LSP) varied from 1?000 to 1?600μmol/(m~2·s) and the apparent photon utilization efficiency varied from 0.014 to 0.06?μmol/mol;The CO_2 compensation concentration(CC) of photosynthesis varied from 57.54 to 72?μmol/mol;The photorespiration in autumn was (0.952?μmol/(m~2·s)).