A novel method was developed for the determination of SiO2-3 in Cyclotella meneghiniana Kiits solution by non-suppressed conductance detection ion chromatography.The chromatography was performed on a Dionex anion AS23(4 mm×250 mm) analytical column and AG23(4 mm×50 mm) guard column with a constant temperature conductance detector.The experimental conditions were optimized，and the optimal chromatographic conditions were using 4 mmol/L sodium carbonate as eluent with a eluent speed of 1.0 mL/min，injection sample volume of 100 μL.The calibration curve of silicate was linear in the range of 0-40 mg/L.The detection limit was 0.017 mg/L.The relative standard deviation(RSD，n=7) for standard solution was lower than 5%.The RSDs for peak area and peak height measurements were 10.9% and 4.8%，respectively.The proposed method was applied in the determination of silicate in Cyclotella meneghiniana Kiits solution in different growing periods，and the spiked recoveries were in the range of 102%-120%.With the advantages of simplicity，good sensitivity，low cost，the method was suitable for the determination of silicate in cyclotella meneghiniana kiits solution.