A track light assembly adopted for a track light has a conduction track having two lateral sidewalls opposing each other, two lateral retaining members extending inwardly from the two lateral sidewalls respectively, a cavity formed between the two lateral sidewalls, and a cutout formed between the two lateral retaining member and communicating with the cavity. The track light assembly further includes an insulation strip disposed in the cavity and having an opening relating to the cutout, and a conduction strip made of conductive materials. The conduction strip is partially disposed in the insulation strip and partially exposed out of the insulation strip via the opening. The track light is provided firm connection to the track light assembly with an easy assembly and removal, the track light assembly can prolong the life thereof accordingly.