The invention provides a GIS basin-type insulator surface defect model. The GIS basin-type insulator surface defect model is characterized by comprising a high-voltage electrode and a ground electrode, a cone frustum epoxy block is placed between the high-voltage electrode and the ground electrode for simulating a basin-type insulator material and structure, and the high-voltage electrode, the cone frustum epoxy block and the ground electrode are in tight contact. The problem that in the prior art, testing cannot be performed when dirt exists on the surface of a basin-type insulator is solved, the requirement for GIS surface defect discharge characteristic study is met, and a novel path is opened for GIS basin-type insulator surface defect discharge characteristic study.