The pathogenesis of preeclampsia (PE) involves a number of biological processes that may be directly or indirectly affected by glucocorticoid (GC) and vitamin D. GC exposure increases the risk of PE, and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) deficiency may result in PE. The purpose of the present study was to confirm the involvement of GC/1,25-(OH)2D3 axis in the pathogenesis of PE. In the study, cortisol levels of PE patients were found to be higher than that of non-complicated pregnancies, while 1,25-(OH)2D3 were decreased in both PE women and GC-induced PE rats. Mechanically, GC reduced 1,25-(OH)2D3 levels via disturbing its biosynthetic and catabolic enzymes, including Cyp3a1,Cyp24a1 and Cyp27b1, especially enhancing the expressions of Cyp3a1, the dominant enzyme for vitamin D degeneration. Moreover, replenishing 1,25-(OH)2D3 ameliorated the symptoms and placental oxidative stress of GC-induced rat PE. The protective actions of 1,25-(OH)2D3 might be explained by its roles in antagonizing the effects of GC on trophoblast proliferation and apoptosis. Together, these findings suggest that GC exposure could lead to PE via dampening 1,25-(OH)2D3 biosynthesis, and GC/1,25-(OH)2D3 axis might represent a common pathway through which PE occurs.