Abstract: Previous studies indicated that the expression of a serine/threonine protein kinase DsSTPK of Dunaliella salina could be induced by salinity stress. In order to study the functions of DsSTPK, the Open Reading Frame (ORF) of DsSTPK gene was obtained through RT-PCR. The target fragment was subcloned into pET32a(+ ), and the recombinant expression vector pET32a(+ )-DsSTPK was transformed into E. coli. BL21 (DE3), then followed by induction of IPTG. The products were purified by His60 Ni Gravity Columns, identified by SDS-PAGE and Western-blot. The results indicated that the recombinant expression vector pET32a(+)-DsSTPK was constructed successfully, the molecular weight of the recombinant protein induced by IPTG was in line with expectation; And the recombinant protein existed both in the supernatant and in the form of inclusion body. Western-blot analysis showed that the recombinant protein could be identified specifically by the anti-his antibody. The research has laid a foundation for further studies on how the DsSTPK works in Dunaliella salina salinity stress signal transduction.