Abstract: Mercury (Hg) and its compounds have posed some significant toxicity to humans. Notably, the organic species methymercury (MeHg) can be bioaccumulated and subsequent biomagnified along the food chain. In inland areas of Southwestern China, rice (Oryza sativa L.) consumption constitutes the primary source of MeHg exposure for local inhabitants. Thus, it is very crucial to reduce the content of methylmercury in rice, particularly for the national food security in the Hg-mining regions. Alternatively, the heavy metals (such as arsenic) can be reduced to accumulate in rice during ridge tillage. This agronomic practice also enchances soil air permeability, facilitating the migration and transformation of redox-sensitive elements in the soil. Ridge tillage is a conventional agronomic measure for water conservation and yield enhancement; however, it remains unclear on the effect of ridge cultivation on the migration of mercury in the soil-rice system. This study aims to investigate the impact of ridge tillage on Hg accumulation in rice, Hg mobilization, and transformation in soil. A field experiment was conducted in the Wanshan Hg mining district of southwestern China. The experimental treatments involved various ridge heights: 7cm (R7), 10cm (R10), 15cm (R15), and 18cm (R18). The flooded treatment with the conventional till (no ridge) served as the control (R0). The results showed that there was some variation from the conventional till to ridge cultivation patterns. Preferable environmental potential was presented to inhibit the uptake of both total mercury (THg) and MeHg in rice grain. Furthermore, the ridge height of 10 cm (R10) treatment also shared the best performance to reduce the total mercury and methylmercury content in rice, compared with the rest treatments of different ridge heights. The total mercury and methylmercury content in rice were reduced by 21% and 37%, respectively, compared with the control. Ridge tillage improved the soil pH value and redox potential (Eh), which were significantly correlated with the MeHg content in rice roots (P<0.05). The content of MeHg in the rice root after ridge tillage treatments (R7, R10, R15, and R18) significantly decreased by 46%-62% (P<0.05), as the ridge height increased. The reason was likely that the MeHg content were reduced in the pore water resulting from ridge tillage. Specifically, the ridge tillage treatments (R7, R10, R15, and R18) significantly decreased the MeHg content in the pore water by 35%-70%, compared with the control (P<0.05). Additionally, the ridge tillage treatments (R7, R10, R15, and R18) also decreased the proportion of Fe-Mn oxide-bound Hg, while there was an increase in the organic-bound Hg, compared with the control. Among them, the proportion of the Fe-Mn oxide-bound Hg decreased from 0.67‰ of control to 0.38‰, whereas the proportion of the organic-bound Hg increased from 66.4% of control to 79.8% in the R10 treatment. Furthermore, the oxide-bound Hg was positively correlated with the MeHg content in rice grain (P<0.01). In conclusion, a ridge height of 10 cm in the paddy fields significantly reduced the content of THg and MeHg in rice grain. These findings can also offer a theoretical foundation for the remediation strategies of mercury pollution in soil, in order to reduce the risk of Hg accumulation in rice.