OBJECTIVE： To establish the mesoporous carbon nano-drug delivery system （MCNs） with chemotherapy drugs loaded and holding photothermal and photodynamic combined effect， and study its anti-multidrug-resistant tumor effect in vitro. METHODS： MCNs was prepared by low-concentration hydrothermal route， and the MCNs surface was carboxylated by the mixed acid ultrasound method to made MCNs-COOH （MCNC）. The morphology and surface properties were evaluated. Adriamycinc （ADR） was loaded into MCNC to fabricate ADR/MCNC via adsorption method. Drug loading capacity was calculated by UV， and drug release profile was investigated by dialysis method. ADR-resistant human breast cancer MCF-7/ADR cells were chosen， and cell uptake and positioning of ADR/MCNC were observed by confocal laser microscopy； cytotoxicity of ADR/MCNC was detected by MTT method； and intracellular reactive oxygen species （ROS） level under NIR irradiation was measured by flow cytometry. RESULTS： The particle size of prepared MCNs was about 90 nm， with carboxyl in surface. The specific surface area was 541.62 m2/g， pore volume was 0.34 cm3/g， and pore size distribution was 2.5 nm， with significant photothermal effect. The drug loading capacity of ADR/MCNC was 47.4％， showing pH/NIR responsiveness release characteristics. It can promote ADR in cell uptake and nuclear accumulation and induce MCF-7/ADR cell to generate ROS under NIR irradiation， with significant inhibitory effect. CONCLUSIONS： MCNs is prepared successfully， and ADR/MCNC has an effect on anti-multidrug-resistant tumors.