As a biopolyester with excellent properties, the potential biomedical applications of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) have gained extensive attention. In this research, PHBHHx was fabricated into nanoparticles (NPs) to encapsulate NVP-BEZ235 (BEZ), an efficient kinase inhibitor/antitumor agent, for tumor targeting therapy. The resulting BEZ-NPs displayed a regularly spherical form with an appropriate diameter at 76.0 +/- 3.6 nm. The encapsulation efficiency of BEZ was 83.7 +/- 3.6%, and the sustained release profiles showed that almost 97% of BEZ could be gradually unrestricted from PHBHHx NPs within 72 h. The nanotoxicity studies revealed a satisfactory biosafety of PHBHHx NPs. PHBHHx NPs presented significantly improved cellular uptake in human prostate cancer cell line PC3, thereby enhancing the antiproliferation ability and kinase inhibitory activity of BEZ in vitro. More importantly, the in vivo real-time imaging demonstrated the adequate tumor targeting and accumulation capability of PHBHHx NPs. The remarkably delayed tumor growth, increased tumor necrosis, and reduced tumor proliferation in PC3 tumor xenograft mice further confirmed the antitumor efficacies of BEZ-loaded PHBHHx NPs. The above results suggest that PHBHHx NPs might be a promising drug delivery vehicle, safe and effective, for tumor targeting therapy.