Manufacturing of microgrooves has become an urgent issue with the wide application of difficult-to-machine materials and stringent surface quality requirements. Existing single processes can not simultaneously provide high processing efficiency, precision, and good surface quality, but hybrid processes provide alternative approaches. Here, we propose a laser-assisted electrochemical machining (LAECM) using an optical fiber-based tool electrode (LAECMOF) in which the form of laser transmission in liquid-core optical fibre could be replaced by optical fiber, with the laser transmitted to the machining area utilizing the optical fiber. The characteristics of laser intensity distribution at the outlet of the optical fiber were studied. Materials removal mechanisms of LAECMOF were also revealed, which contained alternate LAECM at the pulse-on duration and laser-induced thermochemical machining (LCM) at the pulse-off duration, while using a direct pulsed voltage. Performance of LAECM including processing dimension, surface roughness, and materials removal rate (MRR) was experimentally studied considering laser power, voltage, and feed rate. With an increase in laser power, MRR increased by 2.14 times and the depth by 1.64 times, compared to using initial power. Microstructures were processed successfully by using the proposed method. LAECMOF would find wide application in three-dimensional manufacturing and polishing of difficult-to-machine materials.