Abstract: This paper reports the morphology, spore germination means and ecological habits of Arthrinium phaeospermum causing Moso bamboo foot rot. Examination resultS showed that primary characters of conidiophore mother cells, conidiophores and conidia were identical with the descriptions given by M. B. Ellis, but some additional undescribed spores were observed as follows: (1)a kind of ellipitic-clavata conidia; (2) acropetal and catenulate conidia; (3) intercalary and terminal chlamydospores. Conidia germination tests indicated that there are two means for germination: one is to produce a germ tube, the other to form a vesicle conatining a number of very small colorless spores. The results of ecological condition experiment have shown that the optimum temperature and acidity for conidia germination are 28℃ and pH 6; for mycelium growth are 24 ℃～28℃ and pH 6. The addition of sugar(4. 5 % ) can raise the precentage of conidia germination.