Assembly connecting structure of automobile floor beam

An assembly connecting structure of an automobile floor beam is provided with a first connecting piece and a second connecting piece. The first connecting piece is of a hollow cavity structure, is provided with an arc-shaped top face extending towards the front side and the rear side, is connected with the first cross beam in a spot welding mode through an arc-shaped top face front side extending part, a cavity front side wall and a cavity bottom face, and is connected with the end of the longitudinal beam in a spot welding mode through an arc-shaped top face rear side extending part and a cavity rear side wall. The second connecting piece is a T-shaped hollow shell, the upper end and the lower end of the second connecting piece are of an open structure, a longitudinal beam penetrating groove and a cross beam penetrating groove are formed in the side wall of the second connecting piece, the longitudinal beam penetrates through the longitudinal beam penetrating groove, the left side wall and the right side wal