The problem of arsenic (As)-contaminated rice affects the food safety and human health, therefore, it received more concerns in recent years around the world. Previous research indicated that increasing concentration of silicic acid in soil solutions may mitigate As uptake by rice. However, some studies also found that silicic acid can desorb arsenite (iAsIII) from soil solid phase and lead to an increase in As uptake by rice. Therefore, further clarification of comprehensive effects of silicic acid applied on paddy field is necessary. Two rice (Oryza sativa L.) cultivars including TK9 (japonica) and TCS 10 (indica) commonly planted in Taiwan were used in this study, which were grown in two As-contaminated paddy fields located at Minsyong (Ms) and Guandu Plain (Gd), Taiwan, where soil As concentration are 20-110 mg/kg and 100-240 mg/kg, respectively. Based on recommended application rate of 750 kg SiO2 ha-1, there are four calcium silicate application rates: 0 kg (Si0), 750 kg (Si1), 1500 kg (Si2), 3000kg (Si4) SiO2 ha-1 used in this study. The results show that the As concentration in brown rice of TK9 and TCS10 cultivars grown in Gd field were decreased about 15% and 20% after Si application, respectively, which decreased by 2-7% and had no significant difference in Ms soils. In addition, it was observed that the main As species in brown rice was iAsIII and DMA, and the proportion of iAsIII was higher than DMA. Moreover, it was also found that the As concentration in shoot were significantly reduced after Si application, and the extents of decrease in As concentrations of shoot in Gd field was higher than Ms field. The results of growth index show the shoot biomass and grain yield of two tested rice cultivars grown in Gd field under Si treatments were decreased, which may be resulted from As phytotoxicity. However, there was no significant growth inhibition was observed in Ms field. Based on the above results, it suggests the Si application can reduce the As (inorganic As) accumulation in brown rice, the extents of decrease were controlled by the soil properties, As concentrations and rice cultivars. Therefore, it needs to consider these factors when Si fertilizer is applied to As-contaminated paddy soils.