A first substrate of a light bar assembly includes a first edge and a second edge parallel to each other along a first direction. A first connecting end includes a first connecting portion protruding further outward than a second connecting portion. A first bonding pad and a second bonding pad are disposed on the first substrate. First solid-state semiconductor light sources are disposed along the first edge and the second edge. A second substrate, disposed corresponding to the first substrate, includes a third edge, a fourth edge, a second connecting portion, a third bonding pad, a fourth bonding pad, and second solid-state semiconductor light sources. A first connecting device is electrically connected to the first bonding pad and the fourth bonding pad; a second connecting device is electrically connected to the second bonding pad and the third bonding pad to fix the first substrate and the second substrate.