A new design scheme for fast steering mirrors was proposed according to the requirements of a laser launching system for emission accuracy. A flexible hinge was used in two-shaft fast steering mirror structure as the moving transmission device, a linear voice coil motor was as a driving component and a high precision optical grating micrometer was taken to implement the position closed control. The operational principle and drive mode of the fast steering mirror were introduced, and the drive components and an angle measuring device were selected. Then, the structure of the flexible hinge was designed. On the basis of researching the stiffness characteristics of the straight beam flexible hinge, sequential quadratic programming algorithm was used to optimize the critical dimensions of the hinge. Furthermore, a simplified model of the drive components was established, and theoretical models and finite element analysis software were used to calculate and verify the transmission accuracy of the drive assembly. Finally, angle measurement components and autocollimation were used in the measurement of the rotation accuracy of the fast steering mirror. The experimental results show that the mechanical structure of the fast steering mirror is stable, reliable, and the beam control precision can reach to 0.95", satisfying the precision requirements of real-time control of the transmission direction in the laser launch system.