Ultraviolet-B (UV-B) radiation is one of the most important abiotic stress factors that could influence plant growth, development and productivity. Spermidine (Spd) is an important plant growth regulator involved in a wide variety of physiological processes. The study was carried out to investigate the protective role of exogenous on alleviation of UV-B stress in Zea mays L. Our result showed that UV-B stress significantly decreased the growth parameters, total soluble sugars, aminoacid, proline content, superoxide dismutase (SOD), catalase (CAT), peroxidase activity (PD) and Malondialdehyde content (MDA) in both the seedlings, but the combination of Spd pretreatment and UV-B enhanced the vegetative growth characters such as shoot and root length, shoot and root fresh weights and dry weights, photosynthetic pigment, non photosynthetic pigment composition and total soluble protein, total soluble glucose, free amino acid, SOD, CAT, PD, MDA and NR activities. However, UV-B stress induced positive effects on growth characters and biochemical constituents. Therefore appropriate concentration of Spd could be used as a simple, practical and inexpensive method for modulating the effects of UV-B stress in plants.