Abstract: The growth of the Semantic Web has seen a rapid increase in the amount of RDF data. Meanwhile, the de-mand for access to RDF data without detailed knowledge of RDF query languages is increasing. In this paper, some definitions in terms of keyword-based search on Semantic Web data were firstly presented. Then, a large number of popular existing solutions were surveyed according to hybrid and non-hybrid style(including K-A means and K-"A means). In addition,eight representative systems were introduced and compared with each other based on different facets,and their unique features were highlighted in details. Finally, some remaining challenges were discussed, and some future research directions were pointed out.

Key words: Keyword-based search,RDF data,Top-K,Semantic Web