Abstract: Lead-zinc ore samples were digested with HCl-HNO₃-H₂SO₄ mixed acid. Silver, copper, lead and zinc in sample solutions were directly determined by inductively coupled plasma-atomic emission spectrometry. Based on the requirement of improving and enhancing the accuracy and precision, the external conditions such as the dilution factor and the acidity of the solution were systematically studied. The results showed that the quantification is most accurate when the dilution factor of the solution is 1000 and the volume fraction of HCl is between 5% and 10%. The internal element of cobalt was added to measure the relative intensity of the spectral line in order to offset the effect of fluctuations in experimental conditions. The detection limits of the method were 1.96 μg/g for Ag, 6.00 μg/g for Cu, 9.00 μg/g for Pb and 3.00 μg/g for Zn with a precision in the range of 1.41%-7.50% (RSD, n=10). The reliability of the method has been tested by quantification of the elements in National Standard Reference Materials and the results were in agreement with the certified values.