When has China said it will mandate head up displays (HUD)?
2025
Sometime in 2012 CAAC are alleged to have suggested 100% of Chinese airlines should have adopted HUDs by 2025.
It seems the Rockwell Collins Heads-Up Guidance System (HGS) has been trialled and that HGS equipped aircraft are permitted to land at certain airports in low visibility conditions - lower landing minima for HGS equipped aircraft.
Reports mention enhanced vision systems (EFV) and enhanced flight vision systems (AFVS) where the HUD is used to project data, including runway outlines, over the pilot's view of the runway ahead.
The CAAC seem to be actively encouraging this, but I don't find the  word mandatory used in this context.


November 14, 2012, 5:07 PM
Rockwell Collins China managing director Ron Ho believes business for aircraft head-up displays (HUD) in China will soon be looking up. “We have been working with the Civil Aviation Administration of China (CAAC) for the past 10 years on the HUD project, and now it has reached the stage where CAAC will require the Chinese airlines to implement the HUDs into their operations,” he explained.
“This will be done in three phases, I understand,” Ho noted. “During the first phase, 10 percent of all the airlines will be equipped and operating with HUDs. In the [s]econd phase, this will be 50 percent. The third phase will be complete fleet equipage by the year 2025.”

From AINonline - Chinese Authorities Commit To Aircraft Head-Up Display Mandate


FAA has also been coordinating with CAAC. In Aug 2012 FAA hosted a Pacific Rim conference in Long Beach CA identifying key technologies, operations and regulations that could be improved with HUD, advanced PFDs and vision systems. Soon after the conference, the CAAC HUD application roadmap appeared. China has without hesitation laid forth a plan to move the country's civil aviation into a 100% HUD compliant operation by 2025.

From Professional Pilot Magazine - HUD gains favor in Asia Pacific



Start HGS from 2005
End of 2010, 52 B727-NGs
... Primary reference for maneuvering ... is natural vision
Promote airlines using HUD


From CAAC - HUD/EFVS systems in the implement(sic) in China