[ Objective] To investigate the effects of planting date on development and yield of forage maize and to determine the appropriate plant- ing date for forage maize. [ Method] Using forage maize 50 as experimental material, the development of forage maize was observed, and the yield of forage in the later grain filling period and mature stage was measured, after the maize were planted at different dates, r Remltl With the delaying planting date, phenological period was delayed, and the duration of the same growing stage was shortened among different treatments. The shor- test duration days of anthesis maturity period appeared in the treatment of planting in June 15, and the duration days of anthesis maturity period was increased in the treatment of planting in June 30. With the delaying planting date, the height of maize plant in the five leaf stage was increased. The highest plant in the jointing stage appeared in the treatment of planting in June 15. However, the highest plant appeared in the treatment of planting in May 30 after the jointing stage. The number of green leaves per plant was reduced with the delaying planting date in the tasseling stage, and it was increased with the delaying planting date from later grain filling period to mature stage. With the delaying planting date, the fresh matter yield, forage yield and grain yield were reduced. [ Conclusion] The study provides theoretical and practical reference for high-yield cultivation of forage maize.