The invention discloses an experimental device and method for making cracks different in angle with the axial direction of a standard rock sample. The device comprises a positioning device, a fixing device, an adapter and a cutting sheet; the adapter is installed on an output shaft of an electric motor of a rock grinding machine, the cutting sheet is installed on the adapter, the positioning device is installed on an electromagnet of the rock grinding machine, the electromagnet is provided with a positioning cylinder which is matched with a positioning hole of the positioning device, and the fixing device is installed on clamping plates of the positioning device through screws. According to the experimental device and method for making the cracks different in angle with the axial direction of the standard rock sample, the cracks can be prefabricated on the standard rock sample, the designed crack length can be accurately machined, and the cracks of which the included angles with the axial direction ranges from 0 degree to 180 degrees can be accurately machined; a pointer corresponds to scales on a dial, and the number of degrees of the included angles with the axial direction can be obtained. The machining accuracy is high, the machining efficiency can be improved, and the experimental device and method are further suitable for machining prefabricated cracks of other non-standard cylindrical rock samples.