为了探讨用无规位相板实现靶面均匀辐照光学系统的特点，首次进行了靶面在离焦情况下辐照均匀性的实验研究。实验结果表明：靶面在聚焦透镜焦面前后较大范围内均可得到均匀辐照，靶面上光强起伏的平均峰间距小于８μｍ。 In order to investigate the characteristics of uniform irradiating optical system of target surface by using a random phase plate, the experimental research on the uniformity of irradiation of the target surface under defocus condition was firstly carried out. The experimental results show that the target surface can be uniformly irradiated before and after the focal plane of the focusing lens, and the average peak distance of the light intensity fluctuation on the target surface is less than 8μm.