Ｏｂｊｅｃｔｉｖｅ　To observe the effects of intrathecal injections of tyrosine kinase receptor B(TrkB) inhibitor K252a on K+-Cl- cotransporter 2(KCC2) expression in the skin/muscle incision and retraction(SMIR)-induced persistent postoperative pain in rats.　Methods　Fifty two adult male SD rats were randomly and equally divided into four groups, namely the sham group(control group), SMIR group, SMIR+dimethyl sulfoxide(DMSO) group and SMIR+K252a group. Mechanical withdrawal threshold(MWT) was measured at the preoperative day 1 and postoperative days 3, 7, 12, 22 and 32, and KCC2 expression in the spinal dorsal horn was detected at postoperative day 7 by western blot.　Results　Compared with sham group, the MWT decreased significantly at postoperative days 7, 12, 22 in SMIR group[(22.5±2.3), (24.9±1.4), (29.5±2.4) g] and SMIR+DMSO group[(24.0±1.9), (24.8±2.3), (26.7±2.1) g](P<0.05). While compared with SMIR group, the MWT increased obviously at postoperative days 7, 12, 22 in SMIR+K252a group[(31.6±1.7), (36.1±2.0), (38.1±2.1) g](P<0.05). In addition, at postoperative days 7, compared with sham group, the expression of KCC2 in the spinal dorsal horn decreased significantly in SMIR group and SMIR+DMSO group(P<0.05), and no statistical significance in SMIR+K252a group(P>0.05). Compared with SMIR group, KCC2 expression in the spinal dorsal horn in SMIR+K252a group upregulated significantly(P<0.05).　Conclusions　KCC2 variations in the spinal dorsal horn may participate in the modulation of persistent postoperative pain evoked by SMIR in rats.