Abstract: <SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">Nitrate are contained in light calcium carbonate,whose content is an important index influencing the quality of light calcium carbonate.Using sodium salicylate-spectrophotometry method,a simple and fast method with good selectivity for determination of nitrate content in light calcium carbonate was established.When visible absorbance was detected at a wavelenth of 410 nm and concentration of nitrate at 0.50~2.50 mg/L,nitrate had a linear relationship with absorptance of sodium salicylate.Equation of linear regression was y=0.102 2x+0. 002 7,r=0. 999 35. Relative standard deviation was better than 10%,and standard addition recovery was 93%~104%.This method can be applied in real-time monitoring as its determination is simple,feasible,and satifactory for results.</SPAN>