Abstract: From March 2017 to March 2020, the morphological characteristics, 10 Koelreuteria bipinnata var. integrifoliola trees with DBH of 20-25 cm in 5 counties of Huangshan city, Anhui province were selected for observation of morphological characteristics, life habits and history of Periphyllus koelreuteriae, and some were collected for indoor feeding and observation. The results showed that the annual life history of P. koelreuteriae is over-summer type of holocyclic life cycle, with 5 generations a year and overwintered with eggs. From the middle of March to the first ten days of April of the next year, K. bipinnata var. integrifoliola trees germinate while the overwintered eggs hatch into fundatrigenia, which harm to sprouts. In the first ten days and middle of April, apterous viviparous females have virginogenia. In the middle and last ten days of April, a large number of alate viviparous femals. In May, tender leaves and shoots of K. bipinnata var. integrifoliola are covered by P. koelreuteriae larva, and the damage is the most serious. In the first and middle of June, the population of insect decreased with some over summer diapause aphids. In the middle and last ten days of October, eggs overwinter in tree crevices and scars. Except the first generation, the left have overlapping generation. The observation demonstrated that there are damage peaks of P. koelreuteriae in May and October.