The invention belongs to the field of geotechnical engineering, and relates to a ground fracture expansion simulation device and a use method thereof. The ground fracture expansion simulation device comprises a framework, an observation window, a baffle plate, a lower disc support plate, an upper disc support plate, a preserved fracture, a variable-inclination-angle device, a bottom loading deviceand a side wall loading device, wherein an artificial portable rainfall device can also be arranged on the top of the framework; the artificial portable rainfall device controls the rainfall quantitythrough a flow rate measuring instrument. The loading device comprises a bottom loading device and a side wall loading device. The bottom layer base rock in a model box can simulate the influence ofthe positive and reverse fault movement, strike-slip fault movement, strike-slip positive fault movement and strike-slip negative fault movement on the upside covering soil body. In addition, the method has the advantages that the operation process is simple and convenient; economic performance is realized; considered factors are various; the problems of single substrate movement type, movement inclination angle change incapability, obvious boundary effects, rainfall influence ignoring and the like in an ordinary simulation experiment can be overcome.