In order to meet the flexible and reliable operation of the wall climbing robot in the narrow dual magnetic wall, a permanent magnetic adhesion element based on Halbach array was designed. A twodimensional physical model be founded by Ansoft Maxwell software, analyzed by the way of finite element analysis, obtained the distribution of magnetic field and magnetic induction intensity, and analyze the effect of structure par ameters on adsorption properties. By comparing with the traditional permanent magnetic adhesion element of magnetic field, the new permanent magnetic adhesion element with the highly permanent magnet utilization rate and unilateral magnetic field, it could be flexible and reliable walking in generator stator gap. The influence of structural parameters on the adsorption performance was analyzed by using the method of parameter variation. It provided reference data for the design of permanent magnetic adhesion element.