Tree-species preferences of Giant Nuthatch during Spring were examined by observing foraging behavior of Giant Nuthatch (Sitta magna) in Zixi Mountain nature reserve, Chuxiong, Yunnan Province from March to May, 2010. Foraging tree-species, foraging tree trunk size and foraging positions were studied by all-occurrence recording. The results showed that Giant Nuthatch mainly foraged on Yunnan Pine (Pinus yunnanensis), the preference index is 43.89 which was much higher than other species' preference index. 97.46% of foraging time and 96.54% of feeding times were recorded on Yunnan Pine. Both of foraging time and feeding times were significantly different between Yunnan Pine and other species (P<0.01). Bigger Yunnan Pine were preferred, 95.60% of feeding times occurred on trunks that bigger than 15 cm in diameter. Among Yunnan Pines' main trunks, branches, sticks and needle-leaves, 61.32% of foraging time and 57.02% of feeding times were recorded on trunks. There was an extremely significant difference between trunk and the other 3 parts (P<0.01). Interspecific competition, insect species and abundance and morphological characteristics may be the reason of those selections for Giant Nuthatch.