Interlaboratory comparison exercises for determination of activity concentration of gross alpha and gross beta in drinking water organized by the National Institute for Radiological Protection (NIRP), China CDC, have been carried out since 2011 to 2021. The purpose of this work was to assess the accuracy and precision of low level radioactivity concentration for gross alpha and gross beta analysis. The comparisons used the natural water samples and the performance of participating laboratories was evaluated with respect to the reference values using Z-score performance indicator. Over the years, the percentage of laboratories with acceptable results was 80%-92%, the comparison of the acceptable results have increased. The non-acceptance results are mainly due to the uncertainty caused by low detection efficiency and short measuring time.