Polycyclic aromatic hydrocarbons (PAHs) in indoor dust pose significant health risks due to their persistence and carcinogenicity. This study comprehensively evaluates PAH concentrations, spatial distribution, sources and particle size distribution in indoor dust collected across 26 Chinese provinces. Each dust sample was fractionated into six fractions: F1 (1000–2000 μm), F2 (500–1000 μm), F3 (250–500 μm), F4 (125–250 μm), F5 (63–125 μm), F6 (<63 μm). The total concentration of the 17 PAHs (∑₁₇PAHs) ranged from 0.63 to 247 μg·g⁻¹, with a median value of 4.3 μg·g⁻¹. High ∑₁₇PAH concentrations were found in North China. PAHs with three rings and four rings were the most prevalent PAHs, accounting for 80.8% of ∑₁₇PAHs. PAH concentration is negatively correlated with dust particle size, and there are certain differences in the particle size distribution patterns of different types of dust samples. The diagnostic ratios and principal component analysis (PCA) indicated that indoor dust mainly originated from fuel combustion and traffic emissions.