Abstract: Particulate matters are primary pollutants and ubiquitous in most urban areas of China and prove to be an acknowledged risk to human health, whose degree of harm is realated to the particle size.Ultrafine particles (UFPs) with its diameter less than 0.1 μm may have greater adverse health effects compared with larger ones as fine particulate matters(PM₁₀)and (PM_2.5).However, there have been fewer studies and insuffient evidence in this regard.In this review, we analyze recent population-based studies on UFPs exposure and its health impacts and elucidate associations of UFPs exposure with subclinical endpoints changes so as to promote the awreness of UFPs and provide reference for its further research.