Abstract: A pot experiment was conducted to investigate the effects of silicon supply on rice growth and methane (CH₄) emission in paddy field under elevated UV-B radiation. The experiment was designed with two UV-B radiation levels, i.e. ambient UV-B (ambient, A) and elevated UV-B radiation (elevated by 20%, E); with four silicon supply levels, i.e., Si₀ (control, without silicon), Si₁ (as sodium silicate, 100 kg SiO₂·hm^-2) ， Si₂ (as sodium silicate, 200 kg SiO₂·hm^-2) and Si₃ (as slag fertilizer, 200 kg SiO₂·hm^-2). The results indicated that, silicon supply obviously alleviated the depressive effect of elevated UV-B radiation on rice growth, and increased the tiller numbers, chlorophyll content, and shoot and root dry masses. Silicon supply promoted rice growth, which increased with the silicon supply level (sodium silicate). Slag fertilizer was better than sodium silicate in promoting rice growth. CH₄ flux and accumulated CH₄ emission were obviously increased by elevated UV-B radiation, but significantly decreased by silicon application. CH₄ emission was reduced with increasing the silicon supply level. Under the same silicon supply level, slag fertilizer was better than sodium silicate in inhibiting CH₄ flux and accumulated CH₄ emission. This research suggested that fertilizing slag in rice production was helpful not only in utilizing industrial wastes, but also in significantly mitigating CH₄ emissions in rice paddy under elevated UV-B radiation.