If your book keeps getting rejected by publishers, you could keep trying with alternative publishers. You can also ask the publisher for recommendations about how to improve, or what kinds of books are being published so that you can make changes that will eventually lead to getting your book accepted.
Another alternative is to self-publish your book. Going through Amazon is one way to do this. You can do it relatively inexpensively. This may be the best way to get your work out there. One of the negatives of self-publishing is that you also have to promote your book on your own.