Abstract: We used SEM to observe the ultrastructure of the pathogenic Phialophora: Phialophora verrucosa, Phialophora richardsiae, Phialophora parasitica and Phialophora repens. Phialophora verrucosa: It had a ruptured apex of phialide showing typical vase-shaped collarette and the successive formation of basipetal conidia. Phialophora richardsiae: The saucer-shaped collar was seen under the light microscope, showed thickening of the inner wall of the collarette in the SEM. The thickening of the inner wall and the slight evertion of the collarette might be the result of scarring of the collarette after successive formation of conidia. Phia'ophora parasitica and Phialophora repens both had long phiafides. Although the phialidc was longer in the former, and that phialides of P. repens usually arose in dense brushes from branched side branches, but sometimes, it was still difficult to differentiate them, some other characters must be revealed to distinguish them.