The invention relates to a procyanidine substance regulatory factor NtMYB330 as well as an expression vector, a transformant, a kit and a method thereof, and belongs to the technical field of genetic engineering. The amino acid sequence of the procyanidine substance regulatory factor NtMYB330 comprises an R2 repetitive sequence, an R3 repetitive sequence, [D/E]Lx2[R/K]x3Lx6Lx3R structural domain and a VI[R/P]TKAx1RC[S/T] structural domain. The amino acid sequence of the procyanidine substance regulatory factor NtMYB330 is shown as SEQ ID NO:2. The content of catechin in transgenic plant flowers obtained based on the overexpression of the procyanidine substance regulatory factor NtMYB330 is averagely increased by 431.5%, and the content of epicatechin is averagely increased by 406.5%. The result shows that the tobacco NtMYB330 gene has a great application prospect in the aspect of increasing the content of procyanidine in tobacco flowers.