Abstract: Aquaporins (AQPs) are the main channel for water transport across membranes in plants, and studies on maintaining water homeostasis by AQPs have been widely reported in recent years. Among the seven subfamilies of AQPs, Nodulin 26-like intrinsic proteins (NIPs), a plant-specific subfamily, have relatively weak roles in water transport in plants, but play an important function in metalloid transport. The protein structure of NIPs is highly conserved with two structural domains: the NPA motif and the ar/R selectivity filter, which are critical for substrate selectivity. NIPs, as typical metalloid transmembrane channel proteins, can be classified into three subclasses based on the amino acid composition of the ar/R region, including NIP I, NIP II, and NIP III, and the different subclasses have specificity and redundancy in substrate transport. The NIP I subfamily mediates the transport of arsenic and antimony, the NIP II subfamily is involved in the transport of boron, arsenic and germanium, and the NIP III subfamily transports silicon, selenium, boron, arsenic, antimony and germanium. NIPs enhance plant resistance to adversity stress by regulating essential and beneficial metals (boron, silicon and selenium). NIPs regulate harmful metalloids (arsenic and antimony) to ensure food safety and human health by reducing their distribution to seeds on the one hand, and to achieve environmental remediation by hyper-enrichment in plants on the other hand. In addition, as a multifunctional channel protein, NIPs can transport hydrogen peroxide, glycerol, lactate, urea, and ammonia, which play a role in plant signal transduction and various physiological and metabolic activities. With global warming and frequent occurrence of extreme weather, plants will face greater challenges during growth and development. Therefore, NIPs can be considered as target genes for breeding highly resistant crops based on their multiple substrate selectivity and functional diversity. The expression of NIPs in plants is organ-, tissue- and cell-specific, and the abundance of their expression and protein activity are tightly regulated at the transcriptional and protein levels. To further understand the biological functions of NIPs in plants, it is necessary to clarify their regulatory mechanisms. In summary, based on the introduction of the structure and classification of NIPs, this paper focuses on their substrate transport and related biological functions and regulatory mechanisms. It aims to provide key candidate genes for enhancing crop resistance and improving crop yield and quality through genetic engineering techniques.