1、Table of Contents UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington,D.C.20549 FORM 20-F (Mark One)REGISTRATION STATEMENT PURSUANT TO SECTION 12(B)OR 12(G)OF THE SECURITIES EXCHANGE ACT OF 1934OR ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(D)OF THE SECURITIES EXCHANGE ACT OF 1934For the fiscal
2、 year ended December 31,2017.OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D)OF THE SECURITIES EXCHANGE ACT OF 1934OR SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(D)OF THE SECURITIES EXCHANGE ACT OF 1934Date of event requiring this shell company reportFor the transition period from to Commi
3、ssion file number:001-35126 21Vianet Group,Inc.(Exact Name of Registrant as Specified in Its Charter)N/A(Translation of Registrants Name into English)Cayman Islands(Jurisdiction of Incorporation or Organization)M5,1 Jiuxianqiao East Road,Chaoyang DistrictBeijing,100016The Peoples Republic of China(A
4、ddress of Principal Executive Offices)Ms.Sharon Xiao Liu,Chief Financial Officer21Vianet Group,Inc.M5,1 Jiuxianqiao East Road,Chaoyang DistrictBeijing,100016The Peoples Republic of ChinaPhone:(86)10 8456-2121Facsimile:(86)10 8456-4234(Name,Telephone,E-mail and/or Facsimile Number and Address of Comp
5、any Contact Person)Securities registered or to be registered pursuant to Section 12(b)of the Act:Title of each class Name of exchange on which registeredAmerican depositary shares,each representing six Class A ordinary shares,par valueUS$0.00001 per share NASDAQ Global Select MarketClass A ordinary
6、shares,par value US$0.00001 per share*Not for trading,but only in connection with the listing on the NASDAQ Global Select Market of the American depositary sharesSecurities registered or to be registered pursuant to Section 12(g)of the Act:None(Title of Class)Securities for which there is a reportin