By the monitoring and chemical analysis of wet deposition at Liuxihe, Guangzhou, 106 rainwater samples with rainfall depth from 0.7 mm to 268.6 mm were collected and tested during the studying period from June of 2006 to May of 2008. The concentration of some major ions in the precipitation, their seasonal variation, material marine sources and ion balance were studied and discussed in this paper. The main conclusions and understandings were expatiated as followings: (1) There were no obvious point pollutant sources in Liuxihe region and its surrounding area, but acidic precipitation accounts for 69.5% of its total, so it was suggested that acid rain is still a serious problem in this region and the pollutants in rainwater mainly comes from the middle\|distance transmission from the northern and southern polluting areas. For example, the largest NO-3concentration of rainwater in summer and autumn may be a result of more transport of NOx by typhoon and other ocean currents from southern polluting areas of the Pear River Delta to the this region. (2) The annual averaged ion concentration of F-, Cl-, NO-2, NO-3, PO3-4, SO2-4, NH+4, Ca2+, Mg2+, K+, Na+ and Al3+ in rainwater in this region was 3.76, 22.80, 0.45, 25.22, 0.86, 62.9, 41.5, 35.77, 2.93, 5.45, 14.8 and 0.943 μeqL-1 respectively. And there was a relation of power function between rainfall depth and ion concentration in single rainfall events, i.e. the ion concentration increased with decreasing rainfall depth. (3) The acidity of rainwater in Liuxihe was mainly caused by SO2-4, NO-3 and Cl-1, and the acidity is mainly neutralized by the main cations (NH+4, Ca2+, K+, and so on) with higher neutralization factor; The amount of strong acid entering rainwater in the site is 2.053 keq hm-2 a-1, the amount neutralized by the cation of NH+4, Ca2+, K+, Mg2+, Al3+ was 0.865, 0.745, 0.114, 0.061, 0.020 keq hm-2 a-1 respectively. (4) There was a significant monthly and seasonal fluctuation for the ion concentration; the acidic rain mainly appeared in rainy season; while the acidity of rainwater was low in dry season. Such a variation pattern was contrary to those in Beijing and Chongqing. (5) Supposing all Na in rainwater comes from ocean source, the calculation of marine contribution to the component of precipitation indicated that the vast majority of Mg2+ and part of Cl－(80.07%), SO2-4(2.91%), Ca2+(1.86%), K+(6.19%) were from ocean sources, and the ocean sources of F-, NO-3 was very low and can be ignored.