The present study provides a new approach to the study of Australian aboriginal cave and rock paintings from cognitive point of view. It expounds that Australian Aboriginal "dreaming" worldview underpins the basic cognitive structure for their ancestors to understand the objective world. This worldview differs from that of most people in the present world. The aboriginals believe that they lived, live and will live along with their ancestors, and they could communicate with their ancestors anywhere and anytime in the "dreaming" world. Once the "aliens" have some knowledge about its ethical cognitive tendency, its "dreaming" worldview, it will enable them to better understand its primitive civility, which was hundreds of thousands years apart. Meanwhile, it will help the "aliens" better understand Australian aboriginal cave and its rock paintings, and it eventually might offer a new perspective to solve the seemingly unsolvable riddles among the cultural heritages.