Black　phosphorus　nanosheet　(BPNS)　is　a　promising　multifunctional　material　in　the　biomedical　field　with　biodegradability　and　low　side　effects,　however　its　features　are　always　weakened　severely　owing　to　its　poor　stability.　Here,　a　novel　method　is　developed　for　improving　the　defect　of　BPNS　based　on　the　effective　protection　of　poly(lactic-co-glycolic　acid)　(PLGA),　which　preserves　the　stable　photothermal　therapy　(PTT)　effect　of　BPNS　and　biodegradability　of　the　material.　Meanwhile,　doxorubicin　(DOX)　is　loaded　on　BPNS/PLGA　to　get　BPNS/PLGA/DOX　for　further　chemotherapy　and　preventing　the　recurrence　of　tumor　after　PTT.　The　presented　combined　therapeutic　strategy　exploits　the　strengths　and　improves　the　defects　of　BPNS,　thus　developing　an　efficient　and　safe　nanoagent　for　cancer　therapy,　which　affords　and　reveals　the　great　potential　of　BPNS　in　nanomedicine.