In the present study, (NH₄)₂S₂O₃ extraction methods were applied to assess bioaccumulation of methylmercury (MeHg) in rice grains, and inorganic mercury (IHg) concentrations in rice leaves were analyzed during the rice growing time to access the bioaccumulation of IHg in rice leaves. The results show that the IHg concentrations in leaves increased in the rice harvest stage, indicating that the limit or no IHg was migrated to the rice grain. Also, the Hg-contaminated leaves may potentially cause the input of ‘new Hg’ into soil, leading to a vicious Hg pollution cycle in a rice paddy system. Our results indicated that MeHg concentrations in leaves could not be used to predict the MeHg bioaccumulation in rice grain. Meanwhile, MeHg transferred capability from soil to leaves decreased with time, which could be the common effect of the decreased soil MeHg bioavailability and translocation of MeHg from leaves to rice grains.