In　order　to　improve　the　calculation　accuracy　of　air-gap　magnetic　field　and　retarder　brake　torque,　vector　magnetic　method　is　applied　to　eddy　current　field　finite　element　analysis　in　permanent　magnet　retarder,　and　non-linear　permeability　of　rotor　and　the　weakening　effect　in　magnetic　field　generated　by　eddy　current　magnetic　field　are　considered.　By　using　finite　element　simulation　software　and　hybrid　automatic　mesh　generation　techniques,　a　numerical　solution　of　permanent　magnet　retarder　electromagnetic　fields　is　obtained.　Experiments　show　that　the　discrepancy　of　flux　densities　in　the　air　gap　between　measurement　and　calculation　is　below　5%,　and　the　calculated　braking　torque　is　fairly　in　good　agreement　with　the　measured　one.