In this paper, a better random method used for improving the light integrated reflectance in the 18～20 nm spectral region of a soft X-ray multilayer has been developed, a 8% increase in reflectance is obtained. The multilayer is fabricated by magnetron sputtering. The reflectance comparative measurement are used for testing the multilayer. The results demonstrate that the layer thickness disorder yields band broadening and wider view field with respect to periodic multilayer, but accompanied with a reduction in reflectance peak. Techniques of control layer thickness is the keystone of experiment.