Characteristic of seed for Sageretia thea fruits collected from the habitat of harvest season in Jeju and theirgermination ratio in different temperatures were considered. The average weight was 0.2g, average diameter was 7.2㎜,average length was 6.5㎜, and size distribution range was 5.1~10.0mm. The number of seeds per fruit was 1.8, and 1000grain weight was 7.77g with diameter of 3.7㎜ and thickness of 1.7㎜ in size. The fruit maturation was investigated to befrom April 27 to June 1, when the best maturation period was about a week, May 11 to May 18. Also, the fruits grown onMay 4 to May 11 were seen to have the bigger in transverse size and weight with a tendency of the earlier maturation datehas the greater the number of seeds. S. thea seeds pretreated for 24 hours at 50℃ were not germinated, while most of thosepretreated for 24 hours at 4℃ were successfully germinated at any degree of temperature (except at a temperature of 10℃).Particularly, the highest germination rate of 55% was made at 15℃, and plumule and radicle were best grown within thetemperature range of 25℃.