Objective: This study aimed to establish chemiluminescent immunoassay (CLIA) for quantitative determination of theophylline levels in human serum. Methods: To measure the concentration of theophylline (n=122) and evaluate the assay. Results: The linear range of the CLIA method was 0.51:_40 mg/L (Y=1.02X+0.44, r=0.995). The intra and inter CV (coefficient variance) of CLIA were 3.20% and 3.57%, respectively. The average recovery rate was 102.3%. This method was free from interference by brilirubin (<200 µmol/L), hemoglobin (<10 g/L), and triglycerides (<15 mmol/L). Conclusion: This method is simple, convenient and precise for clinical pharmacokinetics study of theophylline.