Water jet guided laser micro-machining is a novel micro-machining technique for hard brittle materials. To investigate and evaluate the effects of water jet guided laser micro-machining on the surface topography changes, highest aspect ratio evolution, and kerf edge variations, water jet guided laser micro-machining experiment was undertaken using Nd: DPSS laser system with the repetition frequency of 20–120 kHz and max. power of 25 W. Surface topography measurements of the untreated and treated specimens were carried out with scanning electron microscope (SEM). The material composition of kerf edge and other area was achieved using energy dispersive spectrometer (EDS). The relationship between water jet guided laser micro-machining parameters, surface topography changes, highest aspect ratio evolution, and kerf edge variations are presented and discussed. The experimental results show that there was no oxidation and cracks on the kerf edge and other surface, aspect ratio of kerf is up to 12.7, so the kerf is very steep, local edge breakage is rarely founded at 350x magnification, cutting speed can up to 1 mm/s. The results showed that performance of the water jet guided laser micro-machining technology is excellent for mono-crystalline silicon cutting. © 2021 Elsevier Ltd