Abstract: The objective of the current study was to exploreSto the biological characteristic performances, such as yield, resistance identification, rice quality, agronomic traits and so on, and yield structure characteristics of ‘Ⅱyou 1259’. The correlation and path nanlysis were made on the yield structures of hybrid rice ‘Ⅱyou 1259’ based on its test results in middle rice. The experimental results and demonstration trails show that ‘Ⅱyou 1259’ is featured by high yield , wide adaptability,susceptible to rice blast In Fujian Province,high susceptible to rice blast in In the middle and lower reaches of Yangtze River , and resistance to rice Seedling blast in Hainan Province. The analysis of yield structure indicates that the contribution of grain number per spike to yield amounts to 57.1%, while spike number per hectare, 1000-grain weight and seed-setting rate total 19.7%, 13.5% and 7.4% respectively; The contributions of spike number per hectare and grain number per spike to total grain number per hectare are 26.3% and 71.8% respectively. The contribution of total grain number per hectare to sink capacity is 95.2% while 1000-grain weight is 4.2%; the contribution of sink capacity to rice yield is 86.3% while seed-setting rate is 13.1%. The keys to high yield of ‘Ⅱyou 1259’ are to cultivate full and large spikes, increase total grain numbers per unit area, enlarge sink capacity.