Rice production with confidence and safety is one of the most important issues in Asian countries. For the past few decades, cadmium (Cd) reduction technique in rice has been clarified. Ministry of Agriculture, Forestry and Fisheries and National Institute for Agro-Environmental Sciences (2002) recommended the flooding water of paddy before and after the heading, and to improve soil with fertilizers. However lots of farmers afraid rumor damage of rice quality and price down, destruction of plow pan at harvest. For the purpose of this study, clarify the relationship between rice Cd and soil phusic-chemical condition during planting period. We measured soil pH and soil Eh continuously, and analyze Cd concentration in both soil and rice. We concluded that: 1) winter-flooded paddy field stabilized soil pH in neutral, and lowered soil Eh before and after the heading, 2) organic fertilizer was effective to reduce Cd in rice, 3) soil pH and Eh were not always the strict indicator of Cd uptake by rice, 4) winter-flooded paddy field positively effected for biodiversity of soil in and around paddy fields, 5) climate condition had minor effect into the Cd concentration of rice.