Abstract: The quality of habitats was critical for sustainability of giant panda populations. The characteristics of the diet bamboo populations were one of the most important indicators for restoration of the habitat. The staple diet bamboo populations were investigated to get characteristics of the diet bamboo populations for giant pandas in Jiuzhaigou Nature Reserve from Jun. 2017 to Apr. 2018. The results showed that 1) the giant pandas in Jiuzhaigou generally preferred to the bamboo individuals at an interval of6.3±0.4mm (p=95%)in the basal diameter with a maximum of 9.62 mm and a minimum of 3.30 mm; 2). The mean basal diameter of the bamboo individuals occurred in the same zone as the giant pandas' habitat was4.79±0.2mm with a maximum of 16.20 mm and a minimum of 1.70 mm (p=95%); 3). The mean population density of bamboos was 35 individnals·m^-2; and the height of most bamboos foraged by giant pandas was between 110cm and 125 cm.