Abstract: In order to ensure the accuracy and traceability of the test results of chlorine content in tobacco by continuous flow method, the sodium chloride of primary reference material was used as the raw material of solution reference material (SRM). The SRM was prepared via weighing, dissolving, repacking and heat sealing and went through homogeneity and stability test. The mass concentration of the SRM was 0.1001 mg/mL valued by gravimetric method. The main factors influencing the uncertainty of the SRM, including mass, purity, volume, homogeneity and stability, were also analyzed, its uncertainty was of 0.0005 mg/mL.