The invention belongs to the technical field of high-precision and high-efficiency milling processing of complex curved surface parts, and relates to a curved-surface partitioned processing trajectoryplanning method based on boundary residual height constraint. The curved-surface partitioned processing trajectory planning method comprises the steps of: defining a residual height at a boundary ofa processing region, analyzing geometric features of the processing region, solving of cutter contact point positions under the boundary residual height constraint, and constructing cutter contact point boundaries; selecting one cutter contact point boundary as an initial processing trajectory according to processing requirements, and calculating a geodesic line of the cutter contact point boundary along a line spacing direction; establishing a functional relationship between the residual height and an arc length between the adjacent cutter contact points, generating cutter contact points recursively along the line spacing direction, calculating an arc length error of the tail end cutter contact point and the cutter contact point boundary, and acquiring adjusted cutter contact points through sensitivity analysis; and connecting the cutter contact points corresponding to the geodesic lines along a feed direction, and completing trajectory planning according to the boundary constraint and step length constraint. The curved-surface partitioned processing trajectory planning method is suitable for partitioned processing of complex curved surfaces, can reduce the gear marks and improvethe processing quality.