As a new micro-machining technology, water-assisted laser machining (WaLM) has a broad development prospect. The invention and main technical contents of WaLM are summarized, the main research achievements in theoretical and experimental fields for each kind of WaLM technology are introduced in detail, and the technical differences and applied scopes of each WaLM technology are discussed in this paper. The WaLM technology has obvious advantages in solving the problems of precision loss and efficiency reduction caused by laser thermal damage. Various WaLM devices and combination technologies also provide the reference for solutions of engineering problems.