Abstract: Flow measurement is critical for the safe operation of lead-cooled fast reactors (LFR), where liquid lithium-lead (LiPb) alloy acts as the primary coolant due to its superior thermal and physical properties. However, the harsh working conditions of liquid LiPb, including high temperature, electrical conductivity, corrosiveness, and intense radiation, render conventional flowmeters inapplicable. Although permanent magnet flowmeter (PMF) shows potential for liquid metal measurement, their application in LFR LiPb systems remains insufficient, with electrode shape and corrosion resistance posing key challenges to accuracy and sensitivity. This study aims to design a high-performance PMF for LiPb flow measurement, investigate electrode shape effects, and optimize structures to enhance sensitivity and reduce high flow rate accuracy degradation. To achieve these goals, a PMF with through-type electrodes was developed to ensure direct LiPb contact and minimize signal attenuation. Molybdenum was selected as the electrode material for its electrochemical stability in LiPb, while high-purity alumina ceramic insulation rings prevented stray current leakage. The PMF incorporated SmCo permanent magnets, a conductive fluid pipe (outer diameter 32 mm, wall thickness 4.5 mm), heat insulation layers, and cooling plates to maintain magnetic stability and suppress thermoelectric interference. Eight electrode shapes were designed: one cylindrical, three frustum-shaped (varying end areas), and four conical (zero end area, varying tail lengths). Three-dimensional finite element simulations were conducted using the magnetohydrodynamics (MHD) module. Mesh sensitivity analysis identified Mesh 4 (48 585 elements) as optimal for accuracy and efficiency. Simulations were performed at 500 ℃ with a flow rate range of 0.1-1.0 m³/h, adopting a laminar flow model and second-order discretization. The control variable method isolated the effects of electrode end area and tail length on performance. Simulation results confirm that the SmCo magnet assembly provides a well-distributed magnetic field, with a maximum flux density of 0.367 36 T at the pipe center. Electrode shape does not significantly affect flow velocity distribution, ensuring measurement deviations stem from electromagnetic effects alone. All electrodes transmit a complete electromotive force (EMF) signals with millivolt-level output. For electrodes of equal tail length, potential difference and sensitivity decrease with increasing end area—conical electrode 1 (zero end area, 2.5 mm tail length) outperforms frustum and cylindrical counterparts. Among conical electrodes, shorter tail lengths enhance performance. Conical electrode 1 maintains the highest sensitivity (degradation rate 0.85%) compared to the cylindrical electrode (1.13%) at high flow rates, as its shape minimizes electric field energy loss at the electrode end. This study concludes that electrode shape is a decisive factor in PMF performance. For through-type electrodes with identical insertion depth and length, smaller end areas and shorter tail lengths significantly improve sensitivity and reduce high flow rate accuracy loss, with conical electrodes offering optimal performance. The designed PMF has molybdenum electrodes, alumina insulation, and thermal protection, effectively addresses LiPb’s corrosion and high-temperature challenges. These findings fill the research gap in LFR LiPb flow measurement and provide a theoretical basis for electromagnetic flowmeter optimization. The proposed design and strategy can be extended to other liquid metal measurement scenarios, advancing high-precision flow measurement for advanced nuclear energy systems.