Abstract: A fragment of 300bp (nap300) in napinB promter region was isolated by PCR from genomic DNA of Brassica napus H165. Nap300 and the corresponding sequence of napinB promoter shared 97% homology. Expression vector harboring the promoter fused with GUS gene was constructed for functional analysis. Tobacco plants were transformed by Agrobacterium tumefaciens-mediated method. PCR and Southern results showed that nap300 had been integrated into genomic DNA of tobacco successfully. Assay of GUS activity in the seeds of transgenic tobacco will be carried out to identify the function of the promoter.