The open reading frame of Spinacia oleracea Betaine Aldehyde Dehydrogenase (SoBADH) was retrieved from Spinacia oleracea and inserted into the Agrobacterium tumefaciens binary vector pBin438, which was driven by CaMV35S promoter, and produced the new binary vector pBSB. A. tumefaciens LBA4404 carrying this plasmid was used in genetic transformation of plants. Forty-five primary transgenic plants were detected by PCR and verified by the Southern blotting from 65 regenerated plants, of which 27 transgenic plants had only one copy of T-DNA. The Northern blotting and Western blotting analysis indicated that the SoBADH gene had been transcribed mRNA and expression protein in the transgenic cotton lines. The testing of SoBADH activity of transgenic plant leaves showed that the enzyme activity was much higher than that of the non-transgenic cotton. The growth of transgenic plants was well under the salinity and freezing stress, whereas the non-transgenic plant grew poorly and even died. Challenging with salinity, the height and fresh weight of transgenic plants was higher compared with those of non-transgenic plants. Under the freezing stress, the relative conductivity of leaf electrolyte leakage of the transgenic cotton lines was lower than that of non-transgenic plants. These results demonstrated that the SoBADH gene could over express in the exogenous plants, and could be used in genetic engineering for cotton stress resistance.