Abstract: Silicon is one of the beneficial elements for rice growth， and natural bentonite is a convenient resource of silicon. This paper investigated the effects of bentonite with different particle size in compound fertilizer on rice growth. The compound fertilizer was prepared by tower granulation process. Bentonite was appended according to different weight ratios as 1%， 3% and 5%. Root application of different compound fertilizer was evaluated for their effects on promoting growth and quality of rice via pot experiment. The dry weight of plant increased with the addition of bentonite with different particle size. A comparison of several treatments showed that addition of both bentonite and nano bentonite increased the dry biomass， fresh weight and root system. With the addition of bentonite and nano bentonite of 3% in compound fertilizer， the dry biomass increased by 9.49% and 34.40%， respectively. Compared to the control， the total nitrogen， phosphorus and potassium contents increased by 6.13% and 21.47%， respectively， and the root dry weight increased by 16.10% and 61.25%， respectively. The statistical results revealed that nano bentonite possessed high activity and bentonite improved the slow-release of fertilizer because of its lamellar structure.