Abstract: Based on the phenology data observed by 7 stations from the Chinese Phenology Observation Network,the change of phenological spring in North China(1963-1996),as well as in Beijing(1963-2005),and its relationship with climate warming were analyzed.The results showed that the phenological spring onset showed remarkable advance in North China mostly introduced by warming winter and spring.Temperature from January to March increased 2.3℃,and 1.7℃ in April,while the beginning and ending of phenology in spring advanced 9 days and 4 days separately which led to 5 days longer in spring.In Beijing(1963-2003),the temperature from January to March increased 3.5℃,and 2.6℃ in April.The beginning and ending of spring advanced 11 days and 10 days separately,but the length of spring was not changed dramatically.

Key words: North China, North China, Phenology in spring, Temperature change