A combined method for detecting and positioning high energy radiation, belonging to the radiation detection and imaging technology field, comprises: arranging scintillation crystals for capturing high energy radiation into a regular array; assembling a plurality of PMTs with different sizes into a combined array where smaller PMT is located at the center of larger PMTs; forming a combined high energy radiation detector by bonding the scintillation crystal array and the combined PMT array with an optical adhesive; when a high energy gamma ray is incident into the scintillation crystal array, scintillation light is generated and amplified by the combined PMT array into electrical pulse signals; then obtaining the position coordinates, energy and time of the high energy gamma ray by processing the electrical pulse signals. The method provides more effective and uniform high-energy radiation detection, has higher spatial and energy resolution, and simultaneously has high-speed response.