Heavy metal cadmium pollution in water is a serious environmental pollution, its pollution degree depends on the content and chemical form of cadmium, and is affected by the original water chemical form. The water chemical ions of rivers have certain depletion effects on water pollutants. Based on this, by taking the Longjiang River in Guangxi as the research object, this paper analyses its water chemical characteristics and ion sources. This shall provide theoretical basis for the later management of Longjiang River. The results show that the water body of Longjiang River mainly includes Ca2+ and HCO-3, account for 65%-89% and 65%-98% of the total cations and anions, respectively. The river is weakly alkaline, the ions of the water are mainly derived from the dissolution of carbonate in the drainage basin, and are mainly affected by natural chemistry.