DA1 peptidase is a key plant protease that is widely present in various plants and plays crucial roles in plant growth, development, and environmental adaptation. In recent years, with the improvement of gene editing technology, the mechanism of function of DA1 peptidase have gradually been elucidated. Considerable effort has been devoted to showing that DA1 peptidase is regulated at the transcriptional and post-translational modification levels. Although there are plenty of studies on specific biological functions of DA1 peptidase, there still lacks systematic and comprehensive summaries of the progress of DA1. This review briefly introduces the molecular structure of DA1 peptidase, summarizes the regulatory mechanisms of DA1 peptidase, and focuses on its biological functions in regulating organ size, participating in salt stress, drought adaptation, and activating immune responses in stress responses. In addition, we have summarized the role of DA1 peptidase in the regulation of vascular cambium activity and auxin signal transduction. This review aims to deepen the understanding of the complex functions and regulatory networks of DA1 peptidase.