The revision of the environmental error of the atmospheric electrostatic field ( EF) instrument is of great significance for improving the accuracy of lightning early warning. Because the existing simulation calculation methods are difficult to accurately restore the true and complex boundary conditions, the Finite Element Method is used to simulate the influence of terrain and surrounding objects on the measurement results of the EF, and revised the error of the atmospheric EF instrument in the actual environment. Compared with the existing methods, the Finite Element Method not only simulates and restores the true boundary shape, but also improves the solution accuracy and calculation speed. The results show that there is a power function relationship between the error revision coefficient of the atmospheric EF meter and the conductor distance when it is located on flat ground. In the shielding distance, the error revision coefficient of mountainous areas has a greater change rate than that of flat ground; the revision coefficient have a quadratic function relationship with the instrument position, and the revision coefficient of mountainous areas is smaller than that of flat ground. Through simulation calculations, it is also obtained that the environmental error revision coefficients of various atmospheric EF instrument stations in Laoshan are all less than 1. For different stations, terrain is the main influence factor of their environmental errors.