Objective: To investigate the inhibitory effect of apatinib-loaded nanomicelles on human umbilical vein endothelial cells (HUVECs) as well as its release pattern and safety. Methods: The release rate and use safety of apatinib-loaded nanomicelles was determined by ultraviolet spectrophotometry method and hemolytic assay, respectively. And then, the inhibitory effect of apatinib-loaded nanomicelles on HUVECs was tested by CCK-8 assay, migration assay and tube formation assay, respectively. Results: The apatinib-loaded nanomicelles showed a transient immediate-release (2 h release rate reached 20.5%) and then a slow release (72 h release rate was 62.9%), and the results of hemolytic assay were negative. The proliferation of HUVECs was significantly inhibited by either apatinib-loaded nanomicelles or free apatinib in a concentration- and time-dependent manner (all P<0.05); the inhibition rate of apatinib-loaded nanomicelles on HUVECs was lower than those of free apatinib within 48 h (48 h IC50: 1.385 μmol/L vs. 0.768 μmol/L, P=0.012), but it surpassed that of free apatinib with time up to 72 h (63.34% vs. 59.70%, P=0.005). The migration and tube formation of HUVECs were significantly suppressed by both apatinib-loaded nanomicelles and free apatinib in a concentration- and releasing time-dependent manner, and the inhibitory effects of apatinib-loaded nanomicelles with 3-d release on migration and tube formation of HUVECs were significantly greater than those of free apatinib (both P<0.05). Conclusion: The apatinib-loaded nanomicelles have good safety and sustained release property. Nanoencapsulation can enhance the inhibitory effect of apatinib on HUVECs and extend its action time window.