A passive microstructured mixer based on micro-ploughing technology with a multi-tooth tool is proposed. The mixer uses multiple three-dimensional nozzles to split one of the liquids into several micro-plumes. The fins on the surface of the nozzles induce a second liquid to generate turbulence around the local surface of the fins. The machining mechanism for fabricating 3D nozzles on a stainless steel sheet by micro-ploughing technology with a multi-tooth tool was studied. The machining process mainly involves four stages: tool-feeding, fin-forming, micro-hole-forming and tool-retracting. Simulation and flow visualization were used to evaluate its performance. The simulation results show the fin structure can induce local surface turbulence. The flow visualization indicates that when the flux is between 0.5ml/s and 3ml/s, the two liquids are fully mixed in 1second.