With the broad application of nanomaterials in cosmetics and other industries, the more and more nanoparticles have been released into the aquatic environment, which leads to a number of inevitable environmental issues. At the same time, they cause a negative effect on all kinds of organism including human being. Hence, the enrichment and detection technologies of nanoparticles in water have attracted more and more attention. Currently, a variety of technologies can be used to detect the concentration of trace nanoparticles, but they all have certain limitations in sensitivity and accuracy. In this paper, the pretreatment techniques such as ultrafiltration, chromatography, solid phase extraction, and cloud point extraction of nanoparticles in aquatic environment are generalized. The common detection techniques of nanoparticles, such as spectrum technology, the inductively coupled with plasma mass spectrometry and electrochemical detection techniques are summarized. Moreover, the further development prospects of pretreatment and detection technologies of nanoparticles are also discussed.