Abstract: By using mathematical statistics method and conducting indoor incubation at constant temperature, we determined the biological zero temperature, effective accumulated temperature and temperature coefficient (Q₁₀) for the development of zygotes of Sepiella maindroni. The result reveals that the biology zero temperature for the development of zygotes of S.maindroni is (6.48±0.44) ℃, and the effective accumulated temperature at which the zygotes develop into early juveniles is (396.91±2.81) ℃ · d. The optimum hatching temperature for the embryonic development of S.maindroni is 18.0~24.0 ℃.