The ORF of FoxO1 gene was amplified by reverse transcription-polymerase chain reaction (RT–PCR) from total RNA extracted from adipose tissues of torafugu Takifugu rubripes. PET–32a/Sirt1，the prokaryotic expression vector，was constructed and transformed into Escherichia coli Rosetta (DE3) for FoxO1 expression. Through IPTG inducting expression，the induced fusion protein was purified and verified by SDS–PAGE and Western Blot. As a result，the full-length open reading frame of torafugu FoxO1 cDNA was successfully cloned，and the recombinant vector was constructed. The expressed fusion proteins induced by IPTG were soluble protein. The fusion proteins with tag His were also purified，and the molecular weight of the recombinant protein was about 110 000.