In order to quantitatively characterize the surface texture structure of aggregate， the surface texture structure information of single-grade aggregate and its mixture was obtained by the laser texture scanner， and the construction wavelength slope spectral density（SSD） was selected as the characterization parameter to study the distribution rule， characteristic parameters and relationship of the surface texture structure wavelength SSD curve of single-grade aggregate and its mixture were investigated. The results show that the SSD curves of the surface texture construction wavelength of the single-grade aggregate and its mixture aggregate are consistent with the Gaussmod function equation， and the determination coefficient R² is higher than 0.99； The prediction equation for predicting the SSD curve of the composite aggregate by single-grade aggregate SSD curve is proposed. The prediction accuracy of the prediction equation for the peak area， peak value of the SSD curve is insufficient， and the prediction accuracy for the node wavelength area below 18.3 mm is higher than that of the characteristic parameters. Engineering practice shows that the characteristic parameters of SSD curve node wavelength area ratio and peak area have a good linear relationship with the interior noise on the road， and the determination coefficient R² reaches 0.957 1 and 0.887 6.