【Abstract】Objective To explore the effect of single intrathecal injection the small peptide inhibitor of mLin10-PDZ1 domain on the behavior of bone cancer pain mouse. Methods 40 male C3H/HeN mice were randomly divided into tumor group(group T,n=32) and sham group(group S,n=8). Osteosarcoma NCTC 2472 cells were inplanted into intramedullary space of right femurs of mice of group T to inducing ongoing bone cancerrelated pain behaviors. The sham group was inoculated by α-MEM without any cells. Pain ethology indexes such as the spontsneous lifting behaviors,the paw withdrawal mechanical threshold(PWMT) were observed on 1 d before inoculation and on 3d,5d,7d,10d,14d after inoculation to evaluate the mouse of bone cancer. On the 14th day after inoculation ,the mice of group T were further divided into control group(group C,n=8) and small peptide inhibitor of mLin10-PDZ1 domain 2.5μg/5μl、5μg/5μl、10μg/5μl (group G1, n = 8, group G2, n = 8, group G3, n = 8). Group G1~G3 were respectively treated by intrathecal injection of the corresponding dose of the small peptide inhibitor of mLin10-PDZ1 domain. Group S and group C were treated by intrathecal injection of the same volume of 10%DMSO. Pain ethology indexes mentioned above were observed at 2h,12h,24h after administration. Results (1)The significant increasing of spontaneous lifting behaviors(13.46 ± 1.44)]) ,the obvious decreasing of PWMT (1 .83 ± 0.23) g were observed on 14th d after inoculation in group T compared with group S and preoperative base level (P<0.05).(2) The spontaneous lifting behaviors were decreased,the PWMT was increased in groupG1,G2 and G3 compared with the base level on 14th d before and group C at 2h after administration(P<0.05). The analgesic effect of group G3 was more conspicuous than group G1 and G2（P<0.05）. At 12h after administration, the spontaneous lifting behaviors were decreased,the PWMT was increased in groupG2 and G3 compared with group C（P<0.05）. No obvious change of pain ethology indexes was observed in group G1（P>0.05）. At 24h after administration,the spontaneous lifting was reduced and the PWMT was rised in group G3 compared with group C,the difference was statistically significant（P<0.05）. Conclusion Intrathecal injection the small peptide inhibitor of mLin10-PDZ1 domain can efficiently improve the behaviors in the mouse model of bone cancer pain.