Objective To survey and analyze the quality assessment of the included studies in the Overviews of reviews (Overviews), so as to provide methodology references for Overviews authors. Methods A computerized search was performed for collecting Overviews in The Cochrane Library (Issue 1, 2010), PubMed, EMBASE, and CBM, and the search time ended by December, 2009. Then the relevant data, such as assessment standard etc, were extracted, and the staple standards were analyzed. Results A total of 43 typical Overviews were included. Thirty-two (74.4%) of them assessed the methodology quality of the included systematic reviews with different standards, including OQAQ (34.9%/15), AMSTAR (9.1%/3), Checklist from DARE (4.6%/2), Assendelft scale (4.6%/2), Effective Public Health Practice Project standards (2.3%/1), self-formulated standards (14.0%/ 6), syntaxic standards (2.3%/1), and other standards (4.6%/2). Ten Overviews (23.6%) assessed the quality of evidence, including eight (18.6%) applied the GRADE system. Only 7 studies (16.3%) assessed the quality of evidence and applied the GRADE system as well. Conclusion The quality assessment in Overviews includes the assessment of both methodological quality and evidence quality. But most Overviews do not assess comprehensively. The methodological quality standards applied in current Overviews are numerous and no standard is acknowledged. Yet, the OQAQ and AMSTAR are applied widely and recommended because they are comprehensive and easy to be conducted. It suggests that Overviews authors should choose appropriate methodological quality assessment standards according to concrete conditions. The GRADE system is much more comprehensive and systematic than other systems, so it is recommended that Overviews authors should apply GRADE to assess the quality of evidence in their studies in order to make the study results more comprehensive and easier for clinical application.