The blonde Swede is reportedly visiting her older brother, Axel, who lives in Shanghai and works as a marketing consultant for the Swedish Trade Council.
Nordegren named her youngest child, a boy, Charlie Axel, after her brother. Her oldest child, Sam Alexis, will celebrate her third birthday on June 18.
"Elin took Sam and Charlie to China but needs to be back in time for Tiger to also be involved with the celebration of Sam's birthday," a friend told People.
Speculation continues to swirl over the state of the Woods-Nordegren marriage after the notorious Woods sex scandal that emerged in November 2009.
Sources close to the couple say child custody is the major concern in an impending divorce as Nordegren is reportedly eager to return to her native Sweden with her children.
Nordegren allegedly hired a London-based lawyer, Walter H. White, Jr. in January to represent her in a divorce from Woods, TMZ reported.
White works at the same London law firm, McGuire Woods, where Nordegren's twin sister, Josefin Lonnborg, is an associate.