A combination of the Kriging surrogate model and the genetic and particle swarm optimization (GA-PSO) algorithm was applied to the design and optimization of the U-shaped electro-thermal actuator with large displacement, based on the local function with four parameters. The multi-physical coupling simulation model of the U-shaped electro-thermal actuator was established and validated by experiment. The displacement from simulation shows a good agreement with that from experiment with different voltages, which ensures the accuracy of the sample data for the Kriging model. A co-simulation using ANSYS and MATLAB was created, which can capture the sample data in batches. The simple random sampling was utilized to get sample points. The displacements of different sample points were obtained as sample data. The Kriging model was established with the sample data and the GA-PSO algorithm was used for optimization based on the established Kriging model. Results show that the Kriging model can replace the simulation model for predicting the displacement of the U-shaped actuator precisely. The monotonic relationship exists between the displacement and each of the four key parameters, which can decide the shape of the actuator. The displacement of the U-shaped actuator increases 35.2% under 18 V after the shape optimization.