The CA B738 appears to have a tail number of B-1976 (it's hazy but you can barely make it out just to the upper left of the rear door).
Flightradar logs (see pic) for the past seven days indicate the aircraft serves a variety of routes from CKG such as: PVG (Shanghai), ICN (Seoul), SYX (Sanya), HAK (Haikou), LYG (Lianyungang), HKG (Hong Kong), YIW (Yiwu), and XMN (Xiamen).
Assuming Q's pic was taken within the last seven days, this flight was taking off to one of those destination.