In order to ascertain the input and output characteristics and variation of Cadmium (Cd) in the typical paddy soils in southern China, this study took the certain rice fields of Xiangxiang City in Hunan Province as research targets to discuss the connection between three input pathways (fertilizer, irrigation water and atmospheric deposition) and two output pathways (surface runoff water and rice straw removal) and the Cd content of soil. The results showed that the net fluxes of Cd between 2017-2018 and 2018-2019 were 3.259 and -1.246 g/(hm²·a) respectively, and the total change of Cd in two years was 2.013 g/(hm²·a). Atmospheric deposition was the main input pathway. The net fluxes in two years were 8.68 and 5.75 g/(hm²·a) respectively and the average contribution rate was higher by 94%. Rice straw was the main output pathway. The net fluxes in the two years were 5.73 and 7.32 g/(hm²·a) respectively, and the average contribution rate was higher by 97%. Through the input-output equilibrium analysis, the soil Cd content showed an increasing trend within two years. Therefore, it was necessary to adopt agricultural management measures such as "straw out from field" to improve the safe use efficiency of the soil. The research results could provide theoretical basis and method for the prevention and control of soil Cd pollution sources in this region.