How do I determine which of two International Conference on Web Services (ICWS 2018) is genuine?
Looking a little closer, the IEEE conference in San Francisco is the one that has prior proceedings, and it has an "Important Notice":


  Note that any other similarly named conferences are fresh starters beginning this year and operated by a different organization in Seattle, Washington that has nothing to do with IEEE.


The thing I can't immediately tell is whether the Seattle conference put on by "Services Society" is real or fake.

That conference says in relation to its proceedings:


  The Proceedings of ICWS 2018 will be published in the Lecture Notes in Computer Science (LNCS) by Springer International Publishing AG. Currently the Abstracting and Indexing services covered by Springer’s data feeds for LNCS proceedings include ISI Conference Proceedings Citation Index (included in Web of Science), Engineering Index EI (Compendex and Inspec databases), DBLP, Google Scholar, IO-Port, MathSciNet, Scopus, and ZBlMath.


I did confirm that the Seattle conference is on the list of upcoming Springer Proceedings. Springer published several prior proceedings related to ECOWS 2004 and 2006, the conference the Services Society conference traces its history to: 


  the International Conference on Web Services (ICWS) was first conceived in June 2003 in Las Vegas, USA. Meanwhile, the First International Conference on Web Services - Europe 2003 (ICWS-Europe'03) was held in Germany in Oct, 2003. ICWS-Europe'03 is an extended event of the 2003 International Conference on Web Services (ICWS 2003) in Europe. In 2004, ICWS-Europe was changed to the European Conference on Web Services (ECOWS), which was held at Erfurt, Germany.


The IEEE conference says it goes back 12 years. 

The Services Society has been a registered non-profit organization in the U.S. since at least 2011, according to this IRS lookup. The Principal Officer on that registration is Zhixiong Chen of Mercy College (the mailing address on the registration matches his office address). 

He mentions on that same profile page:


  President of the Services Society, a non-for-profit organization, promoting collaboration between Academia and Industrial practitioners on Services Computing and delivering relevant open course modules, sponsoring with IEEE conferences like IEEE Services 2010 


So, my best guess is that Services Society is related to some entity that had been involved in running the initial European Conference on Web Services; that conference perhaps became affiliated with IEEE and the name ICWS; Services Society had some minor affiliation with the IEEE ICWS; and now it is running a separate conference of the same name. (In fact, according to an announcement in IEEE Xplore, the Services Society ran the 2009 School on Cloud Computing with the 2009 5th IEEE Congress on Services (SERVICES 2009).)

What I do not understand is why, if that's the case, IEEE would say there is absolutely no link between the two. The poorly sourced ICWS Wikipedia page claims that ICWS is run by both Services Society and IEEE.

It is possible that the Services Society conference in Seattle will have a legitimate conference, and it does have a satellite conference in Shenzhen, China. However, it is definitely NOT the IEEE ICWS. 

If the Chinese Computer Federation conference list does not specify that it is the IEEE ICWS conference, then there is some possibility that the Services Society conference is acceptable to them. In that case, since both the organizing committee for the Services Society Seattle conference and the IEEE San Francisco conference have members at Chinese universities, perhaps if you email them they could help you understand which one is recognized by the CCF.