The HAL1 gene was cloned by PCR strategy and confirmed by sequencing. Its open read frame is 879 bp, encoding a peptide of 294 amino acids (32 kD Protein). A chimaeric construct of HAL1 and Npt II (neomycin phosphotransferase II) was constructed and introduced into commercial cultivars of tomato (Zhong SU No. 5: Lycopersicon escullentum) by Agrobacterium tumefacien-mediated gene transformation. Transformants were selected for their ability to grow and root on media containing kanamycin. Transformation was confirmed by analysis of PCR, Southern blot and RT-PCR. The salt tolerance of transgenic tomato is evaluated by comparing the fresh weight, dry weight, Na+, K+ content of transgenic tomato and control tomato. It is concluded that the over-expressing of HAL1 in tomato could enhance the salt tolerance of the transgenic tomato.