Objective: To observe the therapeutic effect of paclitaxel plus trastuzumab chemotherapy on nude mice transplanted with human breast cancer SKBR-3 cells and its influence on the expressions of apoptosis-inducing factor programmed cell death 5 (PDCD5) and anti-apoptosis factor X-linked inhibitor of apoptosis protein (XIAP) in the tumor. Methods: The subcutaneous xenograft model in nude mice was established by using Her-2-overexpression human breast cancer SKBR-3 cells. After tumor formation, the mice were randomly grouped and treated with paclitaxel plus trastuzumab (combined treatment group), paclitaxel alone (paclitaxel group), trastuzumab alone (trastuzumab group), and normal saline (control group), respectively. The drugs were administered once weekly and after 6 times of administration, the mice were sacrificed, their tumors were harvested and weighed, and the gene and protein expressions of PDCD5 and XIAP in the tumors were determined by qPCR and Western blot analysis respectively. Results: In each treatment group compared with control group, the tumor weight was significantly reduced, the relative expression levels of both PDCD5 mRNA and protein were significantly increased, and the relative expression levels of both XIAP mRNA and protein were significantly decreased, moreover, all above changes were more evident in combined treatment group than those in either single drug treatment group (all P<0.05). Comparison between the two single drug treatment groups showed that the reducing effects of XIAP mRNA and protein were greater in paclitaxel group than those in trastuzumab group (both P<0.05), but no significant difference was noted in other parameters (all P>0.05). Conclusion: Paclitaxel plus trastuzumab chemotherapy can effectively inhibit the growth of Her-2-positive human breast cancer in nude mice, and this action may be associated with its up-regulating PDCD5 expression and meanwhile down-regulating XIAP expression.