Objective To investigate the effect of intrathecal injection of Tanshinone Ⅱ A on bone cancer pain behavior and spinal IL-1 β,IL-6,TNF-α expression.Methods According to the random number table method,84 C3H/HeNCrlVr male mice were divided into:(1) Tanshinone ⅡA 10 μg group:the tumor mice were treated by intrathecal administration (once daily on the days 14-20 after inoculation of tumor cells) with Tanshinone ⅡA 10 μg; (2)Tanshinone ⅡA 20 μg group:the tumor mice were treated with Tanshinone ⅡA 20 μg; (3)Tanshinone ⅡA 40 μg group:the tumor mice were treated with Tanshinone ⅡA 40 μg; (4) normal control group:the mice were given food and water ad libitum; (5) DMSO+Sham group:the sham mice were treated with the same volume of 5％DMSO; (6) Tanshinone ⅡA+Sham group:the sham mice were treated with Tanshinone ⅡA 40 μg; (7)DMSO+Tumor group:the tumor mice were treated with the same volume of 5％DMSO.The mice pain behaviors were assessed with the paw withdrawal thermal latency (PWTL) at the corresponding time points,then the mice were killed and the samples of spinal cord were detected by real-time PCR.Results The basic values of PWTL had no significant differences among all groups (P＞0.05).At day 14 after operation,no significant difference (P＞0.05) was found in the PWTL value between normal control group and the sham operation group.But in tumor group,the PWTL value was significantly lower than that of normal control group (P＜0.05).At day 21 after operation,the PWTL and the level of spinal IL-1 β,IL-6,TNF-α expression had no significant differences (P＞0.05) among normal control group,Tanshinone ⅡA+Sham group and DMSO+Sham group.The PWTL ((6.19± 1.26)s) in DMSO+ Tumor group was significantly lower than that of normal control group((16.01± 1.59)s) (P＜0.05),but the level of IL-1β,IL-6,TNF-α expression was higher than that of normal control group.Compared with the normal group,the PWTL ((9.83±1.26)s;(10.29±2.95) s) of Tanshinone Ⅱ A 20 μg and 40 μg group was higher,and the level of spinal IL-1β,IL-6,TNF-α expression was lower (P＜0.05).The PWTL and the levels of spinal IL-1β,IL-6,TNF-αexpression had no significant differences between Tanshinone ⅡA 10 μg group ((6.67 ± 0.96) s) and DMSO + Tumor group(P＞0.05).Conclusion Intrathecal injection of Tanshinone Ⅱ A plays a role in anti-cancer pain,and inhibition of spinal inflammatory cytokine release may be one of its mechanisms.