The invention relates to a drive axle assembly with an improved lubricating system and solves the problem that in an actual using process of a conventional drive axle bridge assembly, lubricating oil cannot enter a differential mechanism housing fully to lead to poor lubrication inside the differential mechanism. An oil receiving container which is arranged in a protruding manner is cast on a bearing cap, splashing lubricating oil as a result of rotation of a passive bevel gear of active and passive bevel gears can be captured by the oil receiving container which is arranged in the protruding manner is cast on the bearing cap and flows into an annular oil tank structure of a main speed reducing housing assembly through an oil duct on the bearing cap, the lubricating oil enters the annular oil tank structure and flows into a hollow region formed between an oil baffle disc of an adjusting nut and the inner wall of the differential mechanism housing through a slotted structure in the circumference of the adjusting nut, and the lubricating oil in the hollow region will flow into a sunken oil collecting mechanism which is arranged on the inner wall of the differential mechanism housing through the inner wall of the differential mechanism housing along with rotation of a differential mechanism assembly to further flow into an inner cavity of the differential mechanism through an oil via tank formed on the inner wall of the differential mechanism housing so as to lubricate parts in the differential mechanism.