Large high-power solid-state laser facilities have a very high requirement for the total positioning error budget(＜50 μm in general), so it is a very important to improve the stability of structure design.In this paper,the stability design is illustrated for several key optical and mechanical systems in the large laser facility. Then,several kinds of methods,such as reinforced concrete supports,truss structures,vibration isolation,integrated design and inhencing structure rigidness are used to reduce the effect of optical and mechanical structures on the ambient vibration and to improve the structure stablility,and finite element models are established to analyse the stablility of the key optical elements and support structures and to verify that the structure design is reasonable or not.The results show that the maximum rotation angles of key optical elements, i.e. cavity mirrors, Injection Mirror (IM), and the mirror in beam switch module are 0.14, 0.423, and 0.394 μrad, respectively,and their design margins are greater than 1.5.These results indicate that the optical elements and support structures can satisfy the design indices for stability.