Abstract:Flowering habit, pollen fertility, rate of seed setting of natural population of common wild rice was investigated in Danzhou, China. Its flowering period was approximately 2 months long (from early October to early December). In sunny days, flowers opened mainly during 11:30 am to 11:50 am, with the optimum temperature of 29.84±2.27℃ and the relative humidity of 53.33±6.63％. In cloudy days, flowering was delayed 20-30 min. It took 70 to 100 min for each floret from opening to closing including opening stage of 10 to 20 sec, pollen scattering after 50 to 60 sec and closing stage of 1 h. Flowering time was negatively related to wind speed and positively related to temperature. Most individuals had a fertility rate of over 50％ and seed setting rate of less than 10％. Flowering habit of natural population of common wild rice has the difference with common rice in Danzhou .The Strategy of reasonably to utilize and effectly to protect natural population of common wild rice is proposed.