I know exactly what this movie is...

Somebody had the brilliant idea to take the battle of Helm's Deep from the LoTR: Two Towers movie, turn that one scene into an entire movie, and then replace the elves with Chinese people, replace Helm's Deep with the Great Wall, and replace the orcs with dragon monsters.

Then, throw in a few swarming-the-wall scenes duplicated from World War Z zombie schlock, and there we have it!

EDIT: Seems I'm not the only one who noticed! From Allan Koay's review on The Storyboard site: "And now comes The Great Wall, what can only be described as China’s feeble attempt at its own Lord of the Rings,"

And from Filmnomenon: "If Japan had Gojira, and South Korea had that thing from The Host (2006), then (ancient) China now has its screen equivalent—the Taotie. Mega-loads of them, like some kind of World War Z apocalyptic scenario."

Called it.