This paper aims to determine the variation between the temperature on the surface protrusion of cubic lattice metal polished by scanning electron beam and the scanning time. The cubic lattice metal sample after milling was chosen as the research object, the surface protrusion shape and the one-dimensional heat conduction model were analyzed by numerical simulation, the functional relations between the temperature and the electron beam energy density or the electron beam action time were studied by combining theory and polishing test, and the temperature rise curves under the influence of different material properties and protrusion shapes were established through simulation software. The protrusion shape of the milling surface can be simplified into conical, semi-elliptical and hemispherical shapes; the temperature on the surface protrusion was affected by three factors:electron beam energy density, electron beam action time, and undulating topography parameter ratio; the protrusion temperature rise rate is positively correlated with the heat conductivity of materials. When the fluctuating temperature is 200 K higher than the melting point, the surface roughness of 45 steel and AZ91D magnesium alloy is reduced; the temperature rise rate of the fluctuating shape is positively related to the shape ratio, and the temperature rise curve and the shape ratio value of the conical protrusion is similar to those fit by. trigonometric function. When the cubic lattice metal surface is polished by scanning electron beam, by establishing the protrusion temperature change curve, the selection of electron beam process parameters can be guided to predict its surface topography changes.