To improve the accuracy and uniformity of personalized spraying on complex surfaces, a spraying trajectory planning and optimization method integrating raster and spiral trajectories was proposed. A coating accumulation prediction model for complex surfaces was first constructed based on the elliptical double-β model. Then, a high-precision hybrid spraying trajectory suitable for complex surfaces was designed by combining the respective advantages of raster and spiral trajectories. On this basis, the spraying spacing and spraying speed of the raster trajectory, as well as the spraying speed of the spiral trajectory, were optimized using sequential quadratic programming and an improved grey wolf optimization algorithm (IGWO). Simulation results show that the optimized hybrid trajectory provides excellent edge accuracy and coating uniformity for heart-shaped, square, and circular patterns. For the heart-shaped pattern, the edge error was reduced by 59.36%, and the coating thickness variation was reduced by 15.33% compared with the traditional raster trajectory, while the coating thickness variation was reduced by 75.87% compared with the spiral trajectory. The proposed method exhibits consistent and stable performance across patterns with different geometric features, demonstrating its universality and effectiveness for personalized spraying on complex surfaces.