I would put more behind a 14.5x115mm varaint of the QJG02 machine gun then a cannon besides there is no ammo box on the crab walker and the legs would still be very light for the recoil of a auto cannon.
Look at the pictures, its got two hind legs that are mainly there to brace it when firing, as well as what looks like a centerline stand that would also be extended when firing to give it add stability.
My first guess would be that it is designed as a mobile heavy weapons platform for paras, marines and light mountain units. Probably special forces as well.
These crab walkers might also be useful in urban combat, especially if there has been some collateral damage.
At this stage and within the next couple of decades, walkers will not become serious direct competitors to tracked and wheeled armour, but would rather branch off to create new niche position for itself, much like how UCAVs have complemented manned combat aircraft.
Compared to an F22 or even F15, predators and reapers are clumsy, slow, awkward looking and underarmed. That didn't stop them, and those same counters won't stop this thing if the Chinese can get it to work reasonably well and the PLA brass is impressed enough to grant them a contract.