OBJECTIVE： To establish a method to determine and compare the contents of sodium benzoate in medicinal （pharmaceutical excipients and active pharmaceutical ingredients） and non-medicinal （chemical reagents and food additives） grade. METHODS： HPLC was conducted for content determination， SPSS 18.0 software was adopted to compare the results. The column was Purospher STAR LP RP-18 endcapped with mobile phase of acetotrile-0.02％ formic acid （adjusted pH to 4.0 with aqua ammonia） （30 ∶ 70，V/V） at a flow rate was 1.0 ml/min， the detection wavelength was 230 nm， column temperature was 35 ℃， and volume injection was 20 μl. RESULTS： The linear range of sodium benzoate was 10.5-525.3 μg/ml （r＝0.999 9）； RSDs of precision， stability， reproducibility and durability tests were lower than 0.5％； recovery was 99.38％-101.26％ （RSD＝0.56％，n＝9）. The average contents of sodium benzoate in medicinal and non-medicinal grade were between 99.400％-99.875％， but the average content of non-medicinal grade is lower than the medical grade. CONCLUSIONS： The method is accurate and simple with high specificity and good reproducibility， and can be used to determine and compare the content of sodium benzoate in medicinal and non-medicinal grade.