The invention provides a gangway foot plate assembly and a low-floor tramcar, and relates to the technical field of rail traffic. The gangway foot plate assembly comprises two pedals, two circular arcplates, a middle gangway foot plate and a connecting assembly. The sides, provided with arc shapes, of the two circular arc plates are connected with the two sides of the middle gangway foot plate through the connecting assembly correspondingly. The circular arc plates and the middle plate can relatively move. The two circular arc plates are connected with a vehicle body between two adjacent carriages through an elastic component. The sides, not provided with the arc shapes, of the two circular arc plates are lapped joint with the two pedals correspondingly. The two pedals are fixedly installed on the vehicle ends of the two adjacent carriages correspondingly. The low-floor tramcar comprises the gangway foot plate assembly. By means of the gangway foot plate assembly and the low-floor tramcar, the problem that a gangway foot plate device is upwarped to affect passenger passing in the running process of a vehicle is solved, and the problems that the gangway foot plate device in the prior art does not meet the higher requirements of tramcar steering and pitching working condition can be further effectively solved.