Abstract: The lightning is a threat to the safety of flying aircraft, while the division of lightning attachment points and lightning zoning are the first step in lightning protection design. Based on this, Simulation methods based on finite element are used to simulate lightning zoning on the many equal proportion model of civil aircrafts by boundary element method with EM studio of the 3D electromagnetic simulation software CST. The relationship between the size of aircraft and the ratio of electric field intensity at edge of 1A region to aircraft maximum electric field intensity is linearly fitted by MATLAB software. According to the fitting relationship, the lightning zoning of domestic civil aircraft is divided, and the numerical results are compared with the standard theory partition. The results show that the fitting results are effective and have important reference significance for the lightning protection design of civil aircrafts.