The invention relates to a quick-change device for a power battery system of an electric automobile and a battery pack. The quick-change device comprises a fixing bracket and a quick-change bracket, and the quick-change bracket is used for connecting a power battery pack and can be clamped into or drawn out of the fixing bracket in a sliding manner; a locking pressing bar is hinged on the fixing bracket, a locking structure is arranged on the quick-change bracket or the fixing bracket or the locking pressing bar, the locking pressing bar rotates along the hinged position to press the quick-change bracket downwards when the quick-change bracket slides into the fixing bracket, and the locking connection of the fixing bracket, the quick-change bracket and the locking pressing bar is achievedthrough the locking structure. According to the invention, a locking pressing block is matched with the locking structure, so that the mechanical locking of the quick-change bracket in X, Y, Z three directions with six degrees of freedom can be achieved, the connection is more reliable and safer, and the quick locking positioning and quick replacement can be achieved by matching the sliding fit ofthe fixing bracket and the quick-change bracket.