The effects of different substrate materials on the focusing performance of the collecting mirror in the extreme ultraviolet (EUV) radiation-damage-test system including fused silica, SiC and AlSi are simulated and analyzed. Compared with ceramic substrates such as fused silica and SiC, the thermal conductivity of AlSi-based collector mirrors is higher, but in the EUV irradiation damage research system, the maximum temperature rise of the surface of the collector on the AlSi substrate is 1.39 ℃ when the power of 10 W is applied to the 300 mm diameter collector. Although AlSi has larger expansion coefficient than that of fused silica and SiC, the maximum structural deformation of the reflector is 3.51 μm, and the wavefront aberration is increased by 8.071λ and the root mean square radius of the spot is increased by 0.028 μm compared with the ideal non-deformation collector, but the AlSi based collectors can be used in non-imaging systems or systems with low requirements for imaging quality, it has obvious advantage for collectors with large aperture and complex surface.