Objective To detect the serum levels of IL-25 and IL-17 in rheumatoid arthritis (RA) patients and investigate the potential relationship with bone erosion and concomitant interstitial lung disease (ILD). Methods The study enrolled a total of 117 RA patients and 56 healthy subjects as controls. The serum levels of IL-25 and IL-17 were determined by ELISA, and rheumatoid factor (RF) was detected by turbidimetric immunoassay, anticyclic citrullinated peptide (anti-CCP) antibody as well as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were also tested. ILD was identified on high-resolution computed tomography (HR-CT), the degree of bone erosion was inspected by musculoskeletal ultrasonography, and radiographic grade was graded by Sharp-van der Heijde Score (SHS). Disease activity in RA was scored with the DAS28 and visual analogue scale (VAS). Correlation analysis was used to evaluate the correlations of IL-25 and IL-17 in different groups. Results Compared with healthy control group, the serum levels of IL-25 and IL-17 increased significantly in the patients with RA. Compared with bone erosion negative group, the serum level of IL-25 was higher significantly in bone erosion group. The level of IL-25 was higher in the ILD group of RA patients than the non-ILD group. In addition, there were positive correlations between the serum level of IL-25 and RF-IgG (r=0.285), RF-IgA (r=0.314), RF-IgM (r=0.380). Meanwhile, the serum level of IL-17 had the positive correlations with RF-IgG (r=0.198) and RF-IgM (r=0.273). Both of them had no correlations with anti-CCP antibody. Conclusion The serum level of IL-25 is raised in RA patients with bone erosion and ILD.