A dust collection assembly of a vacuum cleaner is provided. The dust collection assembly includes a dust collecting box, a filter, a flow guide unit, an exhaust guider, and an upper cover. The dust collecting box and the flow guide unit are integrally formed in a single body. The dust collecting box includes a first and second dust collecting spaces for collecting foreign objects. The filter is disposed in the inside of the dust collecting space to primarily filter foreign objects during operation of a cyclone. The flow guide unit guides airflow and has small cyclones integrally formed therein, for secondarily filtering the foreign objects in air. The exhaust guider guides airflow and has a plurality of discharge holes through which air filtered by the small cyclone flows. The upper cover is disposed on the upper side of the exhaust guider.