Abstract:We conducted light control experiment on 39 adult Four Eye-spotted Turtle (Sacalia quadriocellata) to determine the influence of photoperiod on the regulation of the seasonal gonadal cycle from October 2008 to September 2009. We divided 39 individuals randomly into 3 groups, short light group (9L:15D, 7♀, 6♂), long light group (15L:9D, 7♀, 6♂) and control group (natural light, 7♀, 6♂) and checked the number and size of follicles and number of shelled eggs by ultrasound technique and by X-ray photography each month. We also made video record on the courtship behavior of male per half-month. Follicles grouth began in August and reached a maximum number in November, with maximum size in December, the result showed the periodic changes of number and size of follicles consistent with previous research. And the results also indicated that photoperiod did influence on the production of the turtles in number and size of follicles, but did not have effect on the courtship behavior of males. The total number of follicles in short control group was larger than that that in control group (LSD P=0.006), but not significant between short and longer light control group (P=0.498), as well as between longer lighter group and control group (P=0.141); the follicle size was shorter in long light group than in control group (P=0.000) and short light group (P=0.002), but not significant difference was found between short and long light control groups.