Abstract: Liquid phase measurement and analysis is one of the important measures to ensure safe drilling operations. It was found in field practices that in the measurement of Ca²⁺, Mg²⁺ and K⁺ using the standard "GB/T 16783.1-2014/ISO 10414:2018" is unable to perform or the measurement results are quite different than the actual situation because of lack of clearly defined titration endpoint and inevitable manmade errors in reading the amount of centrifuged precipitates. To eliminate these problems and to improve the precision of measurement, it is suggested that the standard "GB/T 16783.1-2014/ISO 10414:2018" be corrected using the data collected from filed practice and laboratory experiment. Laboratory experiment results show that, after correction, the cumulative errors in the measurement is effectively minimized and the measurement precision improved. K⁺ ion concentration data from 5 wells show that after replacing the "C-V method" with "C-m method", the measured K⁺ concentration matches the actual K⁺ concentration. Compared with the "C-V method", the "C-m method" has better operability and completely eliminates manmade errors of measurement. It is thus concluded that the "C-m method" is a method that can be used to get accurate measurement results.