The present invention provides a method for analyzing the non-observed effect concentration (NOEC) of a chemical on an organism. The analysis method includes the following steps: 1) conducting a chronic toxicity test on a test organism with a test chemical at different concentrations, and conducting assays to obtain several sets of endpoint effect data; 2) classifying the several sets of endpoint effect data obtained in step 1); and 3) constructing hypothesis testing models with the data classified in step 2), and according to the statistical significance values from hypothesis testing models, among the same set of endpoint effect data, adopting the highest concentration of the test chemical that do not produce a significant effect as NOEC within the set; and among the different sets of endpoint effect data, adopting NOEC of the set with the smallest NOEC value as NOEC of the test chemical on the test organism.