Abstract: For dust online monitoring system, the indexes such as indicated value error can no longer fully reflect the performance difference of different types of light scattering dust sensors, and the tolerance and long-term stability of high concentration dust become important indexes that need to be included in the assessment, and the high concentration flooding experiment can be used as the assessment method for these two indexes. Practice shows that the dust meter with the function of air warping protection can still maintain good metering performance after the high concentration dust flooding test, and can be used for online monitoring of dust in the outdoor environment.