From July to August 2015, the quadrat sampling method was used to investigate summer habitat selection by sambar deer in Wolong National Nature Reserve. Fifteen habitat variables, such as elevation and slope gradient were assessed for 160 quadrats. Of the 160 quadrats, 85 were sites used by Rusa unicolor and 75 were random sites. An optimal model for habitat selection of Rusa unicolor was chosen according to the results of logistic regression analysis and Akaike information criterion (AIC).  The results showed that the key ecological factors affecting the habitat selection of Rusa unicolor in summer were concealment, slope gradient, distance from human disturbance, and distance to water. In summer, Rusa unicolor prefer habitats with good or moderate concealment, gentle slope（< 20 °）, far from human disturbance（> 1000 m ）and near water resources（< 500 m）. Furthermore, the results also suggested that vegetation type affected habitat selection of Rusa unicolor to some extent (χ2= 11.499, df= 4, P= 0.021). Around 92% of the sites used by Rusa unicolor were found in all kinds of forests, and only around 8% were found in the shrubland of Rhododendron sp. and Quercus semecarpifolia located at around 3500 m above sea level.