To achieve the requirement of flexure hinges for specific optical precision equipment, a new triangular bi-axial flexure hinge is proposed. The analysis model for the flexibility of the triangular bi-axial flexure hinges is derived. After that, the linear and nonlinear finite element methods are used to verify the analysis model. Then, the physical dimensions of the hinge are optimized using the multi-island genetic algorithm in conjunction with the finite element method, and the rotational stiffness and center drift are diminished. Static analysis and modal analysis of the hinge are conducted. A test system was built to gage the flexure hinge’s rotational stiffness. The results demonstrated that there was good agreement between the analytically calculated value, simulated calculated value, and experimental value. To summarize, the analysis model met the design requirements of the triangular bi-axial flexible hinge, and the multi-island genetic algorithm effectively optimized the physical dimensions of the hinge and enhanced its performance. The design process provides new ideas for the design of other forms of hinges.