To isolate the plasma membrane intrinsic protein 2 (PIP2) gene and its promoter from mulberry (Morus multicaulis), and to analyse its expression under stress conditions using quantitative real-time polymerase chain reaction (qRT-PCR) analysis, the mulberry MmPIP2 gene was cloned and sequenced. The putative MmPIP2 protein was 282 amino acids long and contained Asn–Pro–Ala signature motifs. Phylogenetic analysis showed that MmPIP2 is highly conserved, exhibiting strong homology with other plant PIP2s. The 5′ flanking sequence was cloned by genome walking and numerous transcription factor binding sites were identified. qRT-PCR revealed that the expression levels of MmPIP2 differed with changes in abiotic stress, indicating that PIP2 is a multifunctional molecule in mulberry. Studying the molecular mechanisms behind adaptations to stress and strengthening stress tolerance in plants are of fundamental importance to mulberry production.