Reflective crack is one of the major technical problems in highway with semi-rigid base, studying its formatting mechanism is of great significance. By means of a numerical analysis method named RFPA, formatting process of reflective crack such as initiation and expansion was studied in asphalt pavement with semi-rigid base. Two-dimensional model of asphalt pavement with cement-treated base was established based on mechanical parameters, thickness and homogeneity of commonly used structural layer in china, symmetrical and non-symmetrical load were both considered, and crack of cement-treated base was set before loaded. First, reasons for crack initiation were studied below the bottom layer subjected to different types of loads. The conclusion showed crack under symmetrical load mainly due to pull destruction while crack under non-symmetrical load mainly due to shear failure. Then, crack expansion in asphalt layer subjected to different load numbers with different homogeneity material was studied. The result showed that with the increase of the load numbers, the deformation in the same level deformation grows continuously. Different homogeneity level of layer material has an important influence on crack expansion; higher homogeneity has better regularity.