Recently, more and more college ranking systems are receiving attention due to the demand and necessity of higher education and college ranking system is a key topic in the field of social choice. However, these rankings have different evaluation criteria that lead to confusion for decision-makers. To address this issue, a simple and practical approach is to aggregate these ranking systems from different sources. In this paper, we conduct an experimental study on aggregation of world university ranking. Specifically, we first classify unsupervised RA methods. Then, we compare the aggregation effects of 28 unsupervised RA methods on five public university rankings.