Crop straw is one of the important agricultural wastes with high silicon content. In this study, potting experiments were used to study the effects of rice straw and husk at different application rates on soil silicon fractions, silicon uptake, aboveground dry matter accumulation and soil fertility, providing theoretical basis and practical guidance for increasing the silicon balance of paddy field and promoting rice silicon uptake by returning organic materials to the field. The trial included seven treatments: control (CK), 0.5% straw (JG1), 1% straw (JG2), 1.5% straw (JG3), 0.5% husk (DK1), 1% husk (DK2), and 1.5% husk (DK3). The results showed that the application of organic materials increased the contents of soil water-soluble silicon, available silicon, organically bound silicon, and amorphous silicon, and increased with the increase of application rate, especially for rice husk application. Compared with CK, the application of medium and high husk significantly increased the content of soil water-soluble silicon by 18.85%~46.58%, available silicon by 11.51%%~118.82%, Organic silicon by 21.88%~51.95%, Fe/Mn-oxide silicon by 3.38%~19.17%, and amorphous silicon by 6.41%~22.14%, respectively. Compared with CK, the application of straw and husk significantly increased the silicon accumulation of rice stems and leaves by 0.60~2.51 times and 1.33~4.08 times, respectively, and the increasing effect of high husk application was the best. Organic materials application did not influence aboveground dry matter. In addition, straw and husk applications increased soil organic matter and available nitrogen, phosphorus and potassium. In conclusion, the application of silicon-rich organic materials can effectively improve soil amorphous silicon content and soil fertility, increase soil silicon availability, thereby promoting rice silicon uptake, and increasing rice biomass to a certain extent. However, husk has more advantages than straw in improving rice silica nutrition, and has certain application prospects in paddy fields.