Plant responses to abiotic stress are closely linked to the dynamics of microtubules, and the structure and function of tubulins are regulated by microtubule-associated proteins (MAPs). MAP70-1 is a microtubule binding protein, which plays a vital role in plant growth and development and stress. In order to reveal the molecular mechanism of MAP70-1 response to drought stress, we used the rootstock M26 of apple (Malus domestica Borkh.) as material, cloned the MdMAP70-1 gene (GenBank No. XM_008390949) by PCR and performed bioinformatics analysis. The ‘yellow pearl’ tomato was transformed by Agrobacterium-mediated leaf disc method and its drought resistance was analyzed. The results showed that: (1) MdMAP70-1 was successfully cloned and its open reading frame (ORF) was 1 860 bp and encoded 691 amino acids，the relative molecular weight was 68.77 kD and the isoelectric point (pI) 8.64. Comparison of amino acid sequences and phylogenetic analysis indicated that MdMAP70-1 contained a conserved domain of MAP70 family and had a closest relationship with VvMAP70-1 (Vitis vinifera VIT_201s0011g05790). (2) Wild tomato was transformed by Agrobacterium-mediated leaf disc method, 12 positive plants were obtained by resistance screening, and 8 overexpressed lines containing target bands (1 860 bp and 680 bp) were obtained by PCR, which proved that the MdMAP70-1 gene had been transferred into tomato. qRT-PCR detected and selected three transgenic lines OE-1, OE-2 and OE-3 with significantly higher expression levels than WT (wild type). (3) Analysis of drought stress resistance of T₃ generation transgenic tomatoes showed that there were no differences in the relative water content (RWC), proline (Pro) content, content of soluble protein (SP), malondialdehyde (MDA) content, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities of overexpressed tomato leaves under drought stress 0 and 5 days compared with control (WT). After 10 and 15 days of stress, compared with WT, the RWC, Pro content, SP content and antioxidant enzyme activities of the overexpressed MdMAP70-1 transgenic tomatoes were significantly higher than those of WT, while the relative conductivity (REC) and MDA contents were decreased. The study have shown that overexpression of MdMAP70-1 gene in tomato can increase the contents of RWC, Pro and SP, activities of SOD, POD and CAT in tomato, reduce the contents of REC and MDA, and enhance the drought resistance of tomato. The results of the study laid a foundation for the use of MdMAP70-1 gene to improve the drought tolerance of plants and the function of microtubule-associated proteins.