Abstract: To analyze the effect of water temperature on growth trait and sex differentiation of redfin puffer (Takifugu rubripes), we reared a full-sib family at four temperatures of 15 ℃, 17 ℃, 19 ℃ and normal temperature (21~25 ℃). The results showed that the growth rate of the fish decreased with decreasing cultivation temperature. The fingerlings in normal temperature group presented the highest growth rate, followed by 19 ℃, 17 ℃ and 15 ℃ in descending order. For fish at 30~90 dph, different temperature groups had similar variation trends in absolute growth ratio and growth index. For fish before 70 dph and those at 80~90 dph, the normal temperature group and 19 ℃ group presented the highest absolute growth ratio and growth index, respectively. We used morphological examination and histological section to identify the ratio of males and females for fish at 180 dph. The percentages of males and females were 86.67% and 13.33% in 15 ℃ group, 70.00% and 30.00% in 17 ℃ group, 56.67% and 43.33% in 19 ℃ group as well as 53.33% and 46.67% in normal temperature group. In conclusion, low temperature produced effectively higher proportions of males and 15 ℃ group was the optimum treatment group.