A novel diffraction ray tracing method on convex surfaces of electronic warfare special aircraft was investigated. Quickly-3D-model of aircraft was carried out, and surface grids were meshed on the model to provide surface discrete grids data. Enough points can be achieved by minutely modeling or interpolating splines and nodes. Base on tracing area was selected and grid nodes were managed, according to Fermat principle, the length of geodesic path between the source and incept point can be calculated quickly and veraciously with the method of improved dynamic programming on the platform surface discrete grids served as. Then, discrete geometrical theory of diffraction(GTD) and uniform geometrical theory of diffraction(UTD) ray tracing on aircraft was realized with the method of recursive method. This work provided an approach for quickly analyzing antenna isolation with numerical method.