Many more Chinese people use mobiles than go online
China Unicom is to stop using Google search on Android handsets.
The second biggest operator in China is believed to be taking the step in reaction to Google's decision to stop offering a censored search service.
Instead of using Google search, handset makers will be able to decide which search service to use on phones that run Google's mobile operating system.
At the same time Google said it would withdraw more of its uncensored search services in China.
The China Unicom deal will first have an impact on Android phones being developed for it by Motorola and Samsung.
The move could be a big blow for Google as China has far more people owning and using mobiles than it does using the net.
Google search looks set to become even rarer in China as it steps back from providing uncensored search services to online firms and mobile operators in China.
Google has more than 12 syndication deals with Chinese firms.
"Over time, we will not be syndicating censored search to partners in China. But we will of course fulfil our existing contractual obligations," a Google spokeswoman in Singapore told the Reuters newswire.
China Unicom will not put Google search on Android phones
If partners prefer to take a censored feed, this could mean that the contracts with Google for search are not renewed.
On 22 March, Google shut the censored search service run through Google.cn and redirected users to an unfiltered feed run from Hong Kong.
The fallout from this decision has already had an impact.
Its search service has been removed from the tom.com portal owned by Hong Kong billionaire Li Ka-shing who is known to be close to the Chinese government.
Reports suggest that Google's decision to use uncensored search via Hong Kong was having mixed results for web users on the Chinese mainland. Some international sites could not be reached and searching for some terms returned blank pages.
"Google.com.hk is not currently being blocked, although it seems that some sensitive terms are," said Google. "However, if you search for a sensitive term and trigger a government blockage, that may affect subsequent searches ... for a short period."
Another hi-tech firm, Go Daddy, has also said it is cutting back on its Chinese operations.
The domain registrar said it would stop registering net domain names in the country because new regulations imposed by the Chinese government require those buying domains to supply names, addresses and colour photos.