Extending beam assembly

The invention relates to an automobile body of an automobile, in particular to an extending beam assembly in an automobile body of an automobile. The invention provides the extending beam assembly, which comprises an extending beam welding element, wherein the extending beam welding element comprises a bottom plate and side plates formed by bending from the two sides of the bottom plate, the tail end of each side plate is bent for forming a first lap joint plate, the end part of the bottom plate is provided with a bottom plate opening expanding bending plate, the end parts of the side plates are provided with side plate opening expending bending plates, and the bottom plate opening expanding bending plate and the side plate opening expanding bending plates define an expanding opening. The extending beam assembly has the beneficial effects that the stress performance of the extending beam assembly can be improved, the replacement for high-intensity materials is not needed, and the cost is favorably reduced.