Abstract: Aiming at the current mask electrolytic processing process curing, process complexity and other problems, a patterned mask electrolytic processing method based on microfine direct-write polymer materials is proposed. The application of the direct-write mask process to the microfine electrolytic machining planar coil process is investigated. The influence law of direct-write processing parameters on the mask is obtained using the one-factor method. The laws of process parameters such as processing voltage, cathode vibration frequency and duty cycle on forming accuracy were obtained using orthogonal experiments. A prediction model for the dimensions of the processed microstructures was established, and a planar microcoil structure with a width of 300 μm was processed on a thin alloy sheet with a thickness of 30 μm using the optimized process parameters, and a response with an impedance change rate of 3.46% was obtained by a network analyzer for the detection of the current sensing effect. The feasibility of direct-write mask applied to microfine mask electrolytic processing is demonstrated.