Black phosphorus (BP) nanosheet is easily oxidized by oxygen and water under ambient environment, thus, reliable BP passivation techniques for biomedical applications is urgently needed. A simple and applicable passivation strategy for biomedical applications was established by encapsulating BP nanosheet into zeolitic imidazole framework-8 (ZIF-8). The resulted BP nanosheet in ZIF-8 (BP@ZIF-8) shows not only satisfied chemical stability in both water and phosphate buffered saline (PBS), but also excellent biocompatibility. Notably, BP nanosheet endows the prepared BP@ZIF-8 with prominent photothermal conversion efficiency (31.90%). Besides passivation BP, ZIF-8 provides the BP@ZIF-8 with high drug loading amount (1353.3 mg g −1 ). Moreover, the loaded drug can be controlled release by pH stimuli. Both in vitro and in vivo researches verified the resulted BP@ZIF-8 an ideal candidate for tumor multimodal treatments.