Objective To establish a novel rat model of chronic skeletal muscle composite injury in the lumbar region, to explore its mechanism and treatment method in depth. Methods Twenty-eight SD rats were randomly divided into control group (n= 10) , Hitting injury model(HIM) group (n= 9),Composite damage model(CDM) group (n= 9) (vertical blow combined with forced prolonged sitting). Open field test, HE staining and PCR sequencing were performed 3 days after modeling. Results The open field distance of rats in HIM group was significantly shorter than that in the CDM group, and both groups had shorter distances than the control group. HE staining showed multiple muscle fiber breaks, significant widening of muscle gaps, uneven distribution of muscle nuclei, and visible congestion in the model group of simple blow injury; In the CDM group, muscle fibers were ruptured, the muscle gaps were slightly widened, and inflammatory cell infiltration was observed between the muscles, especially around the muscle fiber breakage, with muscle fiber nuclei gathering. A volcano plot of the sequencing result suggested significant differences in the Pf4 gene. GO analysis of muscle tissue in model group rats showed upregulation of oxygen binding and carrier activity pathways. Conclusions This study attempted to establish a composite skeletal muscle injury model to study the pathological changes of chronic skeletal muscle injury in the low back pain and evaluate the efficacy of treatment method. It has practical application value in animal experiments for chronic non-specific low back pain.