The type 920 medical ship was given the number 866 a while back and officially joined the navy on the 23rd. You can find articles about it on Sinodefence and on Global Security.
This is the article that talked about its entry into PLAN.
It said that China's first indigenously designed global medical ship has been handed from Guangzhou shipyard to the navy on the 23rd of this month.
This is designed and built by the Guangzhou Shipyard International Company Limited and makes China one of the very few countries in the world to far long range medical rescue capability. This ship's displacements is in tens of thousands and has hundreds of bed, advanced disinfectant and life saving instruments. Each sick room has a nursing station, it reaches level 3A hospital standard. Large hospital ship is an important sign of modern navy. US and many advanced world's hospital ships are converted from civilian ship. This is the largest ship of its class in Asia. It says that in wartime, ship ship provides early medical treatment for injuries on sea and part of the specified treatment, can also support other ships. In peace time, it can be used for medical training on sea and can provide medical treatment for the fleet and distant islands.
Aside from their commentary, we can probably add humanitarian missions to the list of its duties also. Galrahn actually commented on this ship a while back on its humanitarian values. I think this ship will probably end up in SSF, so it can serve in Taiwan scenario, helping those islands in South China Sea and be part of the growing sea-projection part of SSF.