The invention discloses a three-layer sample structure and a method for measuring an ionization current characteristic of an insulating material. The provided three-layer sample structure for measuring the ionization current characteristic of the insulating material is composed of a first blocking material, a tested material and a second blocking material. The blocking material having conductivitywhich is much lower than that of the tested material and having a high injection threshold is used to realize charge injection of a blocking electrode to a sample and outward migration of charges inthe tested material so that a measured current is generated by ionization charges in an insulating material. A measurement method adopts an improved high field intensity conductance measurement system. The tested three-layer sample structure is placed in a measuring device, and the three-layer sample structure is heated to a specified temperature through a high-temperature oven. And the ionizationcurrent characteristic of the material in the tested material sample under temperature and electric field conditions is measured by using a three-electrode system. The structure and the method are mainly used for measuring the current characteristic generated by ionization in the insulating material.