The invention provides a pile foundation bearing capacity self-balanced testing device for a model test and a test method. The pile foundation bearing capacity self-balanced testing device for the model test comprises a model box, a double-action hollow hydraulic load box, a model pile and a hydraulic loading system data collecting system. The model box is used for fixing the whole testing deviceand simulating boundary conditions of a rock-soil layer structure in engineering. The double-action hollow hydraulic load box can achieve vertical loading and unloading. The model pile is connected with the double-action hollow hydraulic load box through threads. The hydraulic loading system is used for providing loading force needed by the test. The data collecting system is used for collecting test data generated in the process that the hydraulic loading system exerts load to the model pile and the double-action hollow hydraulic load box. The pile foundation bearing capacity self-balanced testing device for the model test can achieve repeated testing experiments, so that the determination method of the pile foundation balance point position and the bearing capacity calculation parameterunder the self-balanced pile test conditions, and the pile foundation bearing capacity self-balanced testing device for the model test and the test method have important guidance significance in engineering practice.