The application of boron nitride (BN) nanomaterials in various fields received extensive attention in the past decades, attributed to its extraordinary characteristics: high surface area, low density, excellent thermal stability, mechanical strength, bio-compatible, and excellent corrosion resistance and antioxidant. This article starts reviews the research progress in the synthesis of BN nanomaterials with different dimensions, followed by briefly summarizing the commonly used preparation methods and main applications of BN nanomaterials, focusing on their potential applications in the fields of environmental remediation, energy conversion (oxygen reduction, nitrogen reduction, hydrogen evolution, fuel cell), and biomedicine. Finally, the research prospects of BN-based nanomaterials are proposed, including the challenges for the large-scale preparation of BN nanomaterials and mechanism research. It is expected that this review is beneficial further to understand the current status and properties of BN-based nanomaterials, to promote research and development of the BN nanomaterials in various fields.