In this paper, bioinformatics methods were used to investigate the expression of related genes in the process of injury repair after fracture induced by external force, to provide a theoretical basis for the estimation of fracture injury time. Data set GSE594 was downloaded from the GEO, and the differential genes were screened by R software in 3-day group, 1-week group, 2-week group, 4-week group and 6-week group, respectively. Enrichment analysis of these differential genes was performed using GO and KEGG databases. Cytoscape software was used to introduce differential genes into protein network interaction analysis, where three algorithms were employed to screen the top 15 genes. Venn diagram intersection was used to identify key genes. The content and proportion of 22 kinds of immune cells in control group and injury group after fracture were analyzed using CIBERSORT deconvolution method. Compared with the normal control group, the key genes in the group 3 days after fracture were: IL6、SRC、CASP3、TGFB1、PRKACA、HAPA5; the key genes in the 1-week group were: IL6、MMP9、DCN、ACAN、SDC1; the key genes in the 2-week group were: IL6、MMP9、COL3A1、ACAN、COL2A1、SDC1; the key genes in 4-week group were: MMP9、TIMP1、SPARC、SPP1、APOE、SDC1、CTSK; the key genes in 6-week group were: TIMP1、COL2A1、ACAN、COL10A1、MMP13、SERPINH1、COL5A1、PCOLCE、APOE、CTSK、THY1、FGF5、GPX3. GO functional analysis of the key geneshowed that it was associated with wound healing, ossification, connective tissue development and cartilage development. KEGG analysis showed that P13K-Akt pathway, HIF-1 signaling pathway, focal adhesion pathway and osteoblast differentiation pathway were involved. The key genes play a specific role in the different stages of fracture healing and are related to the time of fracture injury. The results of infiltration matrix analysis of immune cells showed that macrophages increased significantly after fracture and lasted for a long time, which provides a basis for further study of fracture healing process and time estimation of fracture from the perspective of immune cells.