Reproductive cycle of the small abalone, Haliotis diversicolor aquatilis which collected from Seong-san coastal waters, Jeju, Korea were investigated monthly from May 2006 to April 2007 using histological methods. The gonad index (GI) of male and female reached a peak in June ($70.72{pm}5.20$) and July ($55.38{pm}11.73$). Subsequently, GI decreased in September (Male, $21.27{pm}2.91$; Female, $27.75{pm}4.76$) and increased again in October (Male, $48.49{pm}8.39$; Female, $51.36{pm}7.47$), respectively. After that, GI gradually decreased. In March 2007, GI was reached the minimum (Male, $8.46{pm}0.57$; Female, $9.69{pm}0.88$). The reproductive cycle of female and male could be divided into six successive stages ; In female, multiplication (February and May), growing (February to May), mature (April to July), partial spawning (May to November), degenerating (October to December) and recovery (September to October and December to February) stage. In male, multiplication (February and May), growing (March to May), mature (April to July), spawning (June to November), degenerating (November to February) and recovery (September to February) stage. The yellowish granular cells have been observed more in multiplication, growing, degenerating, and recovery stage than mature and partial spawning stage. The results of GI and histological observations of the gonads suggested that this species could be presumed as multi- spawning characteristics more two times in spawning seasons.