Rice-duck integrated farming is a good ecological agricultural practice which has been widely used in China, Japan, and some Southeast Asia countries or areas recently. It was reported that activities of ducks in the paddy field could bring some positive effects on rice growth, but so far a lot of studies in this area seem to be limited in providing only descriptive findings. In this paper, the influence of the rice-duck integrated farming on rice growth and yield characteristics was quantitatively studied and determined using a set of field plot experiments in Guangdong Province, southern China. Results show that the rice-duck integrated farming could decrease rice height and shoot biomass, but essentially increase its root biomass and the ratio of the root mass to the shoot mass. It is indicated that this kind of farming system would improve the lodging resistance of rice to a certain extent, which is important and helpful for rice production, especially in southern China with more storms. Moreover, the rice-duck integrated farming could raise the contents of chlorophyll a and chlorophyll b and their ratio. This would help improve rice photosynthesis capacity and biomass formation, and prevent rice leaves from becoming withered and yellow too early during the growth period. The rice-duck integrated farming could enhance effective tiller number of rice, depress ineffective tiller process while increasing rice panicle number and its percentage and seed setting rate. All these traits would help improve rice yield. These positive effects would possibly be related to the specified water and nutrient management of the rice-duck integrated farming system and to duck activities such as foraging, muddying, trampling, striking, and physical stimulation. The latter seems to be one of the major reasons for influencing rice growth and yield characteristics. However, little is known about this kind of physical interactions between plants and animals at present. Therefore, the mechanisms of these effects and the optimal rice-duck farming structure as well as related field management should be further examined. This study can provide reference for optimization, demonstration, and extension of the rice-duck integrated farming system.