Abstract: Potted seedlings of Bougainvillea glabra ‘Rosa’ which has been planted 1.5 years were used as test materials, interval water control and continuous water control were used, effects of different water control methods on flowering period, flowers, leaf soluble sugar and plant endogenous hormones of Bougainvillea glabra ‘Rosa’ were studied, in order to quantify and form a systematic water-control technology of Bougainvillea glabra ‘Rosa’,and provide data support and technical reference for regulating its flowering period.The results showed that the flowering period of the different water control treatments were consistent with CK.The flowers of continuous water control treatment was significantly lower than the interval water control treatment and CK;GA₃,ABA and IAA mostly showed a downward-rising-falling trend, the change nodes were also more consistent, the IAA of interval water control treatment showed a gradual downward trend;the ABA/GA₃ ratio showed a decreasing-increasing-decreasing trend,and the ABA/IAA ratio showed a gradual upward trend;the soluble sugar content showed a gradual downward trend.The study showed that using interval water control in Bougainvillea glabra ‘Rosa’could effectively increase flowers,improve the quality of flowering and enhance the ornamental value.