Salinity impairs plant growth, limiting agricultural development. It is desirable to identify genes responding to salt stress and their mechanism of action. We identified a function of the Zea mays WRKY transcription factor, Zm WRKY104, in salt stress response. Zm WRKY104 was localized in the nucleus and showed transcriptional activation activity. Phenotypic and physiological analysis showed that overexpression of Zm WRKY104 in maize increased the tolerance of maize to salt stress and alleviated salt-induced increases in O2-accumulation, malondialdehyde（MDA） content, and percent of electrolyte leakage. Further investigation showed that Zm WRKY104 increased SOD activity by regulating Zm SOD4 expression. Yeast onehybrid, electrophoretic mobility shift test, and chromatin immunoprecipitation–quantitative PCR assay showed that Zm WRKY104 bound directly to the promoter of Zm SOD4 by recognizing the W-box motif in vivo and in vitro. Phenotypic, physiological, and biochemical analysis showed that Zm SOD4 increased salt tolerance by alleviating salt-induced increases in O2-accumulation, MDA content, and percent of electrolyte leakage under salt stress. Taken together, our results indicate that Zm WRKY104 positively regulates Zm SOD4 expression to modulate salt-induced O2-accumulation, MDA content, and percent of electrolyte leakage, thus affecting salt stress response in maize.