The embodiment of the invention discloses a stress change and crack propagation direction test device and a method. The device comprises: a confining pressure chamber, a confining pressure loading unit, a fracturing unit, a stress measurement unit and a crack measurement unit, wherein the confining pressure chamber is used for accommodating a to-be-tested rock core; the confining pressure loading unit is communicated with the confining pressure chamber to apply a confining pressure to the to-be-tested rock core; the fracturing unit is connected to a short joint's end located outside the to-be-tested rock core to fracture the to-be-tested rock core; the stress measurement unit is connected to a strain rosette inside the to-be-tested rock core to measure the stress change in a fracturing process of the to-be-tested rock core; and the crack measurement unit is communicated with the confining pressure chamber to measure the crack propagation direction in a fracturing process of the to-be-tested rock core. The stress change and crack propagation direction test device and the method provided by the embodiment of the invention can test the stress change and crack propagation direction in a rock core fracturing process.