Soluble inorganic pyrophosphatase regulates the homeostasis of inorganic pyrophosphate (PPi) in the cytoplasm through hydrolysis. In this study, seven genes encoded for soluble inorganic pyrophosphatase in maize (ZmPPases) were cloned and identified on chromosomes 2, 4, 5, 6, 8, 10, respectively. The relative molecular mass of ZmPPases was varied from 22.8 kDα to 25.6 kDα with the isoelectric point of 4.84 to 6.24. Secondary structure analysis of ZmPPases revealed alpha helix and beta strand motifs. Phylogenetic analysis together with the homozygous proteins in maize, rice, Sorghum, and Arabidopsis suggested three phylogenetic branches of soluble inorganic pyrophosphatases. ZmPPases were localized in the cell membrane and nucleus by transient expression in N. benthamiana. The ZmPPase genes were inducible under salt and drought stress treatments, whereas ZmPPase2.1 (Zm00001d051564) was down-regulated under salt stress treatment. Collectively, this study reported a comprehensive analysis of the sequence and expression of ZmPPases family members, which might provide a theoretical basis for further functional research.