Abstract: Aiming at the shortcoming of carbon fiber reinforced polymer (CFRP) composite with high-resistance resin matrix producing large amount of joule heat damage caused by lightning under the action of lightning current, this paper explored to solve this problem by improving the conductivity of matrix. In order to modify CFRP composite matrix, a conductive filler based on Ag powder was added into the epoxy resin matrix paste and the conductivity of the modified CFRP composite laminate increases 217.30 times in thickness direction. The single D component of lightning current with different peak values was used to conduct lightning damage test on the modified and unmodified CFRP composite laminates. The ultrasonic C-scan image of the damaged area, the residual temperature field of the specimen and simulated pyrolysis damage were compared to analyze the protection mechanism. The results show that the electrical conductivity of CFRP composite laminates is improved by Ag-powder-matrix modification, and the modification effect is the best in thickness direction. Under the condition of peak current of 20 kA, 40 kA and 60 kA, the damage areas of modified CFRP composite laminates decrease by 87.28%, 77.82% and 88.59%, respectively, and the maximum damage depths increase by 147.06%, 130.65% and 119.72%, respectively. Taking the damage volume as the final index, the Ag-powder-matrix modification can effectively reduce the lightning damage of CFRP composite, and the protection mechanism is to reduce pyrolysis and explosion impact by reducing the area of high temperature and the temperature rise range under the action of lightning current.