May you give more info about your experiments? Is it ChIP/ChIP-sec or qRNA/RNA-seq etc.? Is it about specific gene(s) or something else? It is impossible to answer your question without clarification.
Keep in mind that the interaction you are observing may either the direct (transcription Factor A binds regulatory region of gene B and modulates expression) or indirect (transcription Factor A influences expression of one or more genes other than gene B, and these gene products influence expression of gene B).
What else do you know about your two genes? Many transcription factors are well-studied and we often know something about their consensus sequences for binding. You could look for this sequence in the regulatory regions of gene B.
Thank you Amy Klocko ! is there any database or tools that I can check the target genes of transcription Factor A? or the the regulatory regions of gene B?
Well, it really depends on your organism and what databases have been created. For example, eplant has interaction viewers for plants, I believe there is something similar for yeast and fruit flies as well.