Abstract: To understand the reason of filter screen blocking of automobile diesel, the amount of residue by pre-filtering the diesel fuel for the oxidation stability test, the total contamination, the filter-blocking tendency, and the soluble macromolecules with oxidation activity (SMORS) was determined. The results indicate that the colloidal particle formed by conglomeration of organic acid additives and amines in diesel fuels is the main reason for the blocking. The current domestic automotive diesel standards of cleanliness (GB 19147-2013) cannot reflect the reality of the diesel engine cleanliness, and the filter-blocking tendency or total pollution items should be considered.