Color of stigma, percentage of stigma exsertion, pollen fertility, and seed setting rate by self-pollination and under natural conditions were investigated for 40 natural populations of Oryza. rufipogon Griff . collected from north part of Hainan Province . The results showed that there were several kinds of stigma color named brown,purple,white, mixed color of purple and white, mixed color of brown and white. Percentage of stigma exsertion exceed 60%,among which 28 natural populations come up to 80%,and highest percentage of stigma exsertion was 96.7%,. Average percentage of pollen fertility was 25.6%,and over 40% populations accounting for 22.5%.and highest pollen fertility was 91.4%.Seed setting rate under natural conditions was 3.0-53.1% , and seed setting rate of self-pollination was 0-46.8%,.4 natural populations were barrenness.Highest rate of seed setting under natural conditions reached 98.6.The findings may provide reference for further study and breeding utilization of Oryza rufipogon Griff. indigenous to Hainan.