Focus on the problem that the great circle route algorithm calculates complicatedly with great deviation when it is applied to navigation on circular flight segment and tangent swerve between two neighboring flight segments, this paper proposed a guidance algorithm based on planar projection, which is calculated with the plane after Universal Transverse Gauss-Kruger Projection. Finally, the experimental results with VS2010 show that this algorithm is an effective method of navigation on circular flight segment and tangent swerve between two neighboring flight segments, besides, constant-velocity and arrival on time can be achieved on this simulation platform.