Abstract: Indoor and field experiments show that there existed a significant difference between the counting results of conventional and filtering sieve methods for sampling and analyzing crustacean zooplankton. The amount of crustacean zooplankton by conventional method was lower than that by filtering sieve counting. Statistical analysis shows that the difference was significantly notable. This paper discussed the possibility for causing the difference. The conventional method should be improved, otherwise, it would lower the accuracy of water quality evaluating based on quantitative index of crustacean zooplankton.

Key words: Crustacean zooplankton, Quantification, Sampling and counting, Evaluation