Drug nanocrystal has become an important technology for poorly water-soluble drug delivery, and it is highly desirable to understand their formation mechanism and structure evolution pathway. Here we used curcumin as the model drug and studied in detail its nanoprecipitate structure evolution from a micromixer. Curcumin initially precipitated out as amorphous nanospheres, and then went through amorphous aggregation before transforming into needle-shaped crystals. The results clearly show a nonclassical crystallization pathway for curcumin nanoprecipitation.