A new compound named BSF-A (1) as a plant growth regulator was isolated from the culture filtrate of Botrytis squamosa, and the structure of 1 was elucidated to be I-methyl hydrogen 3-phenyl-2,2' -iminodipropionate by the spectroscopic data of 1 and its methyl ester (2). At a concentration of 300 ppm, 1 and 2 promoted root growth by about 220% compared to that of the control.