Based on the structural characteristics of laser deposition formed metal thin-wall workpieces, the confirmatory test of subarea annular scan is conducted to reduce the temperature gradient of laser deposition formed layers and the residual stress of workpieces. The experimental results show that the usage of subarea annular scan paths can reduce the residual stress of formed parts effectively. An algorithm for generating the subarea annular scan paths is proposed. First, in order to avoid warping deformation caused by the long line scan, a subarea algorithm based on the extreme point search within the scan line limit length threshold is proposed according to the scan line limit length of laser deposition forming, and used for partitioning the independent contour group. Then based on the structural characteristics of thickness-changeable thin-walled workpieces and according to the optimization criterion of wall-thickness, the midline scan and annular scan are combined as an algorithm for the generation of subarea adaptable annular scan paths. Meanwhile, in order to avoid the over-cladding of the transition zone between scan rings, the endpoint offset algorithm is adopted to achieve a smooth transition connection between scan rings. Finally, in order to reduce the temperature gradient of layer surface and the residual stress of workpieces, a sequential optimization algorithm for subarea scan is proposed based on the four-color theorem.