Abstract: This study examines various testing techniques for the fineness evaluation of stone powders, including the Blaine air permeation method, negative pressure screen analysis, water flushing filtration method, and laser particle size analysis, focusing on the stability of these techniques based on statistical analysis and SEM images. Results show that the Blaine method is effective and is the most stable method in the fineness evaluation of stone powder. The two sieving methods are simple and easy to achieve, but their test results are usually unstable because the rock lithology and particle surface characteristics has a great impact on stone powder grinding. Results of the laser particle size analysis are in good agreement with those of the Blaine method. This study suggests that the laser analysis should be adopted to characterize particle grading when a high accuracy is required.