At the present time, it is proved that non- protein- coding RNAs(ncRNAs) play very important roles in the cellular process of translation and relates to Human Severe Diseases. From the NONCODE database 15 diseaserelated ncRNA sequences are selected in this paper, which play regulator roles and relate toAlzheimer Disease and Cancer. Based on Z-curve theory, we map and analyze the Z curves of the studied sequences. By comparing the curves, the statistical features of the Z-curve are obtained. We find that there are almost same curves and base content for one kind of ncRNAs playing same roles. And there are differences of Zn-n curve in different organisms. The conclusion is that the Z-curve is connected with the type or function of ncRNA and organisms.