Field experiments were conducted on the cultivation of ratoon rice using the widely used Yongyou indica-japonica hybrid rice varieties Yongyou 1540 and Yongyou 4949 as experimental materials and the indica-hybrid rice variety Longliangyou 534 as control materials to study the ratoon characteristics and yield formation of Yongyou indica-japonica hybrid rice planted as ratoon rice. The results showed that there are significant differences in the ratoon characteristics between indica-japonica hybrid rice and indica- hybrid rice. The dominant regenerated nodes of the indica-japonica hybrid rice Yongyou 1540 and Yongyou 4949 were the 4th and 5th nodes from top at the lower nodes， which produced a sum of 81.9% and 68.9% of effective panicles with 89.6% and 72.5% of the yield contribution in YongYou 1540 and YongYou 4949， respectively. The panicle length and the number of grains per panicle of these two nodes were significantly higher than that of the 2nd and 3rd nodes from top， showing a decreasing trend from the bottom to the top. The 2nd and 3rd nodes from top at the higher nodes of the Longliangyou 534 were dominant， producing 71.5% of effective panicles with 72.5% of the yield contribution. The spike rate， ratios of effective panicle and yield contribution of were 89.4%， 74.6% and 79.2% for regenerated seedlings of YongYou 4949 within 1-7 d after the first harvesting， significantly higher than those of regenerated seedlings within 8-12 d and 12 d above after the first harvesting. The panicle length and the number of grains per panicle in regenerated seedlings of Yongyou 1540 and Yongyou 4949 were significantly higher than those of Longliangyou 534， with yield increase of 21.6% and 17.3%， respectively. It is indicated that the strong regeneration ability of the low nodes， long panicles， and large number of grains per panicle in regenerated seedlings of Yongyou indica-japonica hybrid rice are the key factors that make it easy to achieve high yield when planted as ratoon rice.