According to Caixin, the cases will be offered to all iPhone 4 customers by the carrier as a "free gift." Apple's latest handset goes on sale in mainland China on Sept. 16.
In July, after reports of antenna issues with the iPhone 4 reached a deafening buzz in the tech community, Apple announced it would give away free cases to all iPhone 4 purchases made through Sept. 30. Customers can order their free case through the iPhone 4 Case Program App Store software.
The report did not indicate whether China Unicom's complimentary case will be mailed after the purchase, or made available to the customer when they buy their iPhone 4.
Earlier this month, a Wi-Fi-enabled 8GB iPhone 3GS was released by China Unicom. Apple's previous phones sold legitimately in the nation of over one billion did not have Wi-Fi, because the Chinese government had temporarily banned the technology.
Following the launch of the iPhone 4, China Unicom is expected to soon offer Apple's iPad for sale.