Taking winter fallowing double cropping rice as contrast and adopting small area experimental method in fields, this paper studied the effects of different winter cover plants, such as ryegrass, milk vetch, rape and potato on rice biological characteristics and its yield economic traits in southern China double-cropping rice production areas. The results showed that planting winter cover crops can promote rice growth and development and increase rice yield. The number of effective tillers of early rice increased by 456 800/hm2, 592 000/hm2, 116 800/hm2 and 160 200/hm2, respectively; the spikelet number per panicle increased by 6.46, 9.75, 1.7 and 4.04 grain per panicle, respectively; the 1000-grain weight increased by 0.24 g, 0.12 g, 0.16 g and 0.43 g, respectively; the grain yields of early rice increased by 409.70 kg/hm2, 536.44 kg/hm2, 97.97 kg/hm2 and 298.48 kg/hm2, respectively. The economic characteristics and yield variation trend of late rice were similar to those of early rice.