The company's owners have also agreed to deliver intellectual property owned and used by the Powertrain engines business to the Chinese as part of a wide-ranging collaboration.
The deal with SAIC is still awaiting formal approval by the Chinese authorities but filings at Companies House reveal that MG Rover signed a deed of assignment with the Chinese on August 5.
Although the company has admitted it is in talks with the Chinese carmaker, details about the discussions have not been known until now.
An MG Rover spokesman confirmed that the deed of assignment represented the company's commitment as its part of a deal which is regarded as crucial to the car company's long-term survival.
"We have reached a technical transfer agreement and the filings at Companies House are part of the legal process. The transfer is legally binding, which is a measure of our confidence that the deal will be approved," he said.
The spokesman would give no details of what technology was being transferred to the Chinese or what MG Rover and Powertrain could expect in return. Full details of the collaboration will not be delivered until the Chinese government has approved the deal - possibly at the turn of the year.