The invention discloses a stress loading device and system for constructing a stress fracture animal model and a method, and belongs to the technical field of animal experiment models. The device comprises a tissue fixing unit for fixing experimental animal skeletons, a laser displacement sensor is arranged at one side of the tissue fixing unit, and a stress sensor is arranged at the other side of the tissue fixing unit. A linear actuator is arranged at the other end of the stress sensor, and the tissue fixing unit, the stress sensor and the linear actuator are coaxially arranged. A linear guide rail is further arranged below the tissue fixing unit. The invention further discloses a controllable stress fracture animal model construction system based on the stress loading device. The system comprises the stress loading device, a real-time data collecting and processing module and a PC side LabVIEW control program. The device is precise and controllable in loading strength and time, and the success rate of establishment of the model can be effectively increased.