SHANGHAI, Sept. 24-- LinkedIn, the world's largest professional social network, signed a strategic cooperation agreement on Wednesday with Didi Kuaidi, car service Uber's major rival in China, hoping to seize a bigger market share.

The agreement was signed during the 8th US-China Internet Industry Forum in Seattle.

In China, Didi's social ride-sharing service Didi Hitch will let users connect to the app using their LinkedIn profiles. Didi Hitch started operations in June this year and 5 million car owners have registered for the service, according to a statement of Didi Kuaidi.

LinkedIn will help Didi Kuaidi on recruitment and training in the United States, where it has invested 100 million U.S. dollars on Lyft, a U.S.-based ride-hailing company, it said.

Founded in 2003, LinkedIn has more than 300 million users worldwide.China's LinkedIn users topped 10 million as of July this year after the company launched its Chinese-language site in February 2014.

Didi Kuaidi now provides 3 million daily rides covering 80 Chinese cities through private car services for 80 percent of the market share, and a 90-percent share, or 3 million daily rides, for taxi-hailing services, according to data from consulting firm Analysys International.