In this paper, using the ‘Xiangzamian 14’ as materials, we have cloned the full-length cDNA sequence of ABP1 gene of cotton by RT-PCR method. The sequence is 792 bp in length and shares a 99% identity with the cDNA sequence of ABP1 gene of the Upland Cotton in GenBank. Semi quantitative analysis shows that, the gene is expressed in cotton leaves, flowers and fibers, the expression amount in leaves is the highest, those in flowers and fibers are a little lower ABP1 gene is highly expressed in the term of rapid elongation of cotton fiber while it is lower expressed in other terms of fiber development .By constructing the ABP1 gene cDNA into the carrier of the cotton ABP1 over expression vector and taking the NPT II as selection marker, by Agrobacterium mediated transformation of cotton, we have obtained 6 Kan resistant plants, including 3 plants whose ABP1 expression level has been raised. The plants with ABP1 overexpressing show normal growth and development, but the change of their fiber length is not significant, which indicates that the increase of the expression level in ABP1 cotton fiber cells has no significant effect on the cell elongation The results have shown that ABP1 gene may not be a key regulate factor in fiber elongation.