In order to explore the causes and countermeasures for straighthead disease of paddy rice grown under waterlogged conditions，a pot experiment was carried out to study the effects of addition of different reducing materials on growth of two rice cultivars varying in their resistance to the disease.The experiment consisted of twelve treatments including three reducing materials（rice straw，ferrous sulfate and sugar) and four potential amendments with five replications.Two rice cultivars（Chuanxiangyou 9838 and Chuanguyou 7329) were employed and grown under waterlogged conditions throughout the growing season.It showed that the two treatments，20 g·kg-1 rice straw and 5 g·kg-1 sugar，strongly impacted tillering of the two rice cultivars.Effective tillers of Chuanxiangyou 9838 were reduced by 40% and 25% by the two treatments，respectively，and those of Chuanguyou 7329 were equally reduced by 45.8% compared to the control.Rice grain yield increased firstly with an increase in rates of straw added and then decreased，and thus，the treatment with 20 g·kg-1 rice straw produced the lowest rice yield，19.7% and 46.1% lower for Chuanxiangyou 9838 and Chuanguyou 7329，respectively，than that with the control.Addition of ferrous sulfate，however，produced the higher rice yield than the control for Chuanxiangyou 9838，and all the other treatments achieved much higher rice yield than the straw 20 treatment.Rice straw treatments significantly enhanced contents of Fe2+ and Mn2+ and decreased Eh values of the soil，which were well correlated with rates of rice straw added; while the treatments of sugar and ferrous sulfate nonsignificantly impacted contents of Fe2+，Mn2+ and Eh values.Among the four treatments with addition of different amendments on the basis of rice straw，only lime and sodium borate alleviated straighthead disease to some extent at rice seedling stage.The piledup rice straw in the alltime waterlogged paddy field from previous harvest could be the main reason for the straighthead disease of next rice season.The released toxic reducing substances from the residual rice straw decomposition，thus，impeded plant growth and finally resulted in rice yield reduction.In the alltime waterlogged paddy rice region，application of reasonable rate of rice straw can promote rice growth and significantly increase rice yield as compared to most of the treatments.