〔Abstract〕 Objective To study the effect of long non-coding RNA(LncRNA) HAGLR on the expression of NOD-like receptor pyrin domain-associated protein 3(NLRP3) inflammasome and fracture healing in tibial fracture(TF) mice and to explore the mechanism. Methods First, HAGLR in osteoblast MC3T3-E1 was silenced byin vitro.Cell viability was detected by CCK-8 assay, cell apoptosis was detected by TUNEL assay, and the expressions of bone alkaline phosphatase(BALP) and osteocalcin were detected by qPCR.Western blot assay was used to detect the expressions of RUNX2,phosphorylated RUNX2(p-RUNX2),NLRP3,cysteine aspartic protease 1(Caspase1),apoptosis-associated spot-like protein(ASC) and interleukin-1β.TF mouse models were established by tibial fracture operation in mice.HAGLR was overexpressed in the model mice, and RUNX2 was silenced or an inflammatory body inhibitor MCC950 was added on the basis of overexpression of HAGLR.The expressions of HAGLR and RUNX2 were detected by qPCR,and the expressions of insulin-like growth factor(IGF-1) were detected by Western blot.microCT was used to measure the volume of mouse callus(MBV) and the total tibial wet weight. Results The apoptosis rate of MC3T3-E1 cells increased and the expression levels of RUNX2,p-RUNX2,BALP and osteocalcin decreased(P<0.05).The expressions of NLRP3,Caspase1,ASC and IL-1β increased(P<0.05).Compared with healthy tissue, the expressions of HAGLR and RUNX2 in TF mice decreased.Overexpression of HAGLR promoted the expressions of HAGLR and RUNX2 in TF mice, and increased the expression of MBV and tibia wet weight and IGF-1(P<0.05).Silencing RUNX2 on the basis of overexpression of HAGLR resulted in decreased expression of MBV,tibial wet weight and IGF-1 in TF mice(P<0.05).However, the addition of NLRP3 inflammasome inhibitor MCC950 on top of the overexpression of HAGLR resulted in increased expressions of MBV,full-length tibia wet weight and IGF-1(P<0.05). Conclusion LncRNA HAGLR promotes the healing of tibial fractures by activating RUNX2 and inhibiting NLRP3 inflammasome.