Abstract: Various experimental methods were used to test natural resistance to moulds of the timber of eleven bamboo species, and the timber of Mao bamboo (Phyllostachys edulis (Carr.) H. de Lahaie) of different ages and from different positions on the stem. Bamboos were from north Zhe-jiang, the People's Republic of China. The results from analysis of variance and multiple contrasts were as follows:(1) The sequence of natural resistance of the timber of eleven bamboo species to the moulds from high to low was Phyllostachys edulis f. luteosulcata (Wen) Chao et Renv., P. edulis (Carr.) H. de Lahaie, P. meyeri McClure, P. viridis (Young) McClure and P. nuda McClure, P. iridenscens C. Y. Yao et S. Y. Chen and P. nigra Munro var. henonis (Miff) Stapt ex Rendle, P. nidularia cv smoothsheath McClure, Pleioblastus amurus Keng f., Phyllostachys angusta McClure, Pseudosasa amabilis Keng f.; the first two were resistant bamboo timbers and the last four were sensitive timbers, there was significant difference between them; interactions of bamboo speciespretreatm-ents and bamboo speciestemperatures and humidities existed.(2) The resistance to the moulds of winter-felled Mao bamboo timber increased with the age of the bamboo, the timber of 9~12 years old Mao bamboo was significantly more resistant than that of 3~8 years old ones; the timber from the upper part of the Mao bamboo stem was significantly resistant than that from the middle and lower part of the same stem.