The sequence between translation initiation site of a bidirectional gene pair(TIGR Locus:LOC_Os09g39540 and LOC_Os09g39550) has been predicted as a bidirectional promoter. This promoter was acquired from the genomic DNA of Minghui 63 by PCR and named as BDP1 and inserted into the promoter function analysis vector pDX2181 in forward and reverse directions (named BDP11 and BDP12). BDP1 was identified as an endospermspecific bidirectional promoter in transgenic plants with GUS histochemical staining. The expression efficiency of the two directions were low. The promoter fragment was extended 123 bp downstream from the end nearer the transcription start site. The new promoter named as BDP2 was inserted into the promoter function analysis vector pDX2181 in forward and reverse directions (named as BDP21 and BDP22). The expression pattern of the BDP2 was the same as BDP1. The expression efficiency of BDP21 and BDP22 were higher than that of BDP1.