A field experiment with four treatments of rice-duck farming systems was conducted in the Zengcheng Teaching and Research Base of South China Agricultural University to further understand the effects of this farming system on the physiological characters of rice. The results showed that rice-duck farming could decrease the plasma membrane permeability and the malondialdehyde and proline contents of rice leaves, but increase their soluble sugar content and superoxide dismutase, peroxidase and catalase activities. This indicates that this farming system had positive effects, improving the rice plant resistance and postponing leaf aging, being of significance on the rice growth and development.