Solar radiation is strongly absorbed by soot aggregate. And the atmospheric radiative properties will be affected by the change of aggregate morphology. Based on fractal theory, the morphological properties of soot aggregates are studied using the cluster-cluster aggregation (CCA) model. The superposition Tmatrix method is employed to perform extensive computations of extinction, absorption and scattering properties of soot aggregates with varying state of compactness and size. The relationship between the morphology and radiative properties of aggregates is discussed. Firstly, the radiative properties of different size and different morphology of aggregates are analyzed with the change of the volume fraction. Then, the absorption, scattering and extinction cross-sections of a fixed morphology aggregate are analyzed with changing particle size. Finally, an essential data for detecting soot aerosol concentration can be provided by the value of absorption cross-section of our results.