Abstract: The physiological state of neutrophils is closely associated with various diseases. Traditional sorting techniques suffer from operational complexity, while existing microfluidic methods are prone to clogging and inadvertent cell activation. To address these limitations, this study proposes a microfluidic system based on a linear Halbach array for the high-efficiency sorting of neutrophils from whole blood. The system integrates a linear Halbach array with a rack-shaped ferromagnetic structure and employs a negative selection strategy. By utilizing an optimized magnetic field gradient to precisely capture immunomagnetic bead-labeled non-target cells within the channel, the system successfully isolates high-purity, unlabeled neutrophils. COMSOL simulations confirmed that the proposed ferromagnetic structure significantly enhances local magnetic field intensity. Experimental results demonstrated that when processing 10 μL whole blood samples, the system achieved a sorting purity of over 95% across various flow rates, providing a novel tool for high-quality sample preparation in clinical diagnosis and immunological research.