Abstract: In order to explore how many times Branchiostoma could lay eggs or produce sperms at the individual level per year, the changing course for the gonadal development of Branchiostoma floridae from the second to the fourth instars was observed for three years. Then, the annual reproduction of different individuals was recorded and the annual reproduction frequency of Branchiostoma floridae at the individual level was analyzed. The results showed that the reproductive period of Branchiostoma floridae lasted from April to December. During this period, the female individuals could lay eggs 5-9 times per year, with an average of 7.4 times, while the male individuals could ovulate 4-9 times, with an average of 6.4 times. The individuals at the second instar could reproduce 4-9 times, with an average of 7.3 times. The individuals at the third instar could reproduce 5-7 times, with an average of 5.7 times. The individuals at the fourth instar could reproduce 4-9 times, with an average of 7.4 times.