The analysis of orthogonal rotational factor tinder maximum variance is made ofthe standardised annual rainfall series of China over the past 40 years for objective demarca-tion of regions. Results show that 10 regions can be found.each marked by a dryness/wetnesstrend typical of its own. For example,the drying treidis most noticeable in North China andthe mid to upper reaches of the Huanghe,some degree of wetting is found in NW China,theHuaihe and the mid to upper catchment of the Changjiang and.vibration occurs in the long-term trend of the mid-lower Changjiang. NE China, the Zhujiang basin and S China coastalareas.The rainfall in 1980s is a bit less than that of 1950s.