The concentration of silica in groundwater and mineral water was determined by inductively coupled plasma-atomic emission spectrometry(ICP-AES).After a more sensitive analytical line of silicon was chosen,the effects of operating conditions of the ICP spectrometer on the analysis results were investigated,at the same time,the impact of coexisting ions on determination results of SiO2 was also considered and eliminated.The transmit power of 1 350 W,observation height of 12 mm,the nebulizer pressure of 0.20 MPa and the pump speed of analysis of 75 r·min-1 were selected by experimental conditions.Under the optimum analytical conditions of spectrometer,the method was used for the determination of SiO2 in groundwater and mineral water with the detection limit of 0.017 mg·L-1,recoveries between 94.10% and 103.8%,and relative standard deviation(RSD)≤3.06%.Compared with the results of silicon molybdenum yellow spectrophotometry,the results were basically consistent with the relative deviation ≤3.00%.In conclusion,the method is simple and efficient with high precision and accuracy,and can be used for research and routine production.