Nanocrystals are nanoscale (1-1000 nm) dispersion systems in which small numbers of surfactants or polymers are used as stabilizers to disperse insoluble drug particles in water or oil. Nanocrystals enjoy not only high drug content, but also a simple and mature preparation process. At present, 24 nanocrystals products that have been marketed mainly focus on enhancing the solubility and bioavailability of poorly soluble drugs. And recent years have witnessed an increasing number of research reports on target drug delivery of nanocrystals through particle size control and surface modification. This paper mainly introduces three targeting strategies for prolonging the in vivo circulation time of nanocrystals, increasing the affinity for tumor cells and achieving the response to internal and external stimuli, and discusses the current challenges in the application of nanocrystal technology to targeted anti-tumor drugs.