Objective To observe the effect of the UbcH10 gene silencing on inhibition effect of doxorubicin against in vivo tumor formation of drug-resistant breast cancer MCF-7/ADR cells. Methods An MCF-7/ADR-UbcH10-RNAi cell line with UbcH10 gene silenced was established. Then MCF-7/ADR-UbcH10-RNAi cells and the control cells at logarithmic phase were inoculated into nude mice to establish the subcutaneous tumor model. Doxorubicin or normal saline was administered for a consecutive of two weeks, and then one week later the tumor volumes were determined to analyze the effects of UbcH10 gene silencing on inhibition of tumor formation by doxorubicin. Meanwhile, Western blotting analysis was used to examine the protein expression of UbcH10 and BCL-2; the relationship between UbcH10 and chemosensitivity of tumor cells was analyzed. Results The MCF-7/ADR-UbcH10-RNAi cell line with UbcH10 gene silenced was successfully established with the lentiviral experimental system. The nude mice tumor models were established three weeks after subcutaneous inoculation of tumor cells. The tumor inhibitory rate was 4.16% in the doxorubicin group, which was not significantly different from the control group (P>0.05); while the tumor inhibitory rate was 41.8% in UbcH10-RNAi+doxorubicin group, which was significantly higher than that in the control group (P<0.05). The results of Western blotting analysis showed that the expression levels of UbcH10 in MCF-7/ADR group, MCF-7/ADR+doxorubicin group, and MCF-7/ADR-UbcH10-RNAi+doxorubicin group were 0.81±0.16, 0.78±0.12, and 0.18±0.04, respectively, with the latter being significantly lower than the former two (P<0.05); BCL-2 protein levels in tumors were consistent with those of UbcH10. Conclusion UbcH10 gene silencing can markedly enhance the in vivo sensitivity of drug resistant breast cancer cells to Doxorubicin.