The objective of this research is to investigate the plasma pharmacokinetics and bio-distribution of liposomal daunorubicin plus tamoxifen in breast cancer murine models through intravenous administration. Daunorubicin and tamoxifen plasma levels in pharmacokinetics studies were determined using HPLC. Biodistributions of various carriers loaded with a cyanine dye (cy7) were evaluated using in vivo imaging. After administration, free daunorubicin and tamoxifen were rapidly cleared out from the blood following a two-compartment kinetic model. The clearances and AUC (0-∞) of daunorubicin were (means ± SD): 0.028 ± 0.005 L h-1 kg-1 and 367.489 ± 56.979 μg mL-1 h-1 (liposomes), and 2.235 ± 0.347 L h-1 kg-1 and 4.546 ± 0.704 μg mL-1 h-1 (free drug). By ex vivo imaging 24 h after injection, the fluorescence intensity of liposomal cy7 plus tamoxifen in tumor region was obviously higher than that of free liposomal cy7. In conclusion, tamoxifen can improve pharmacokinetics profile of liposomal daunorubicin with enhanced therapy for breast cancer.