During asteroid exploration missions, the spacecraft needs to make an investigation into the characteristics of the asteroid after approaching it. In this paper, the performance of the fly-around mapping orbits and flyby mapping orbits were evaluated. The stable fly-around orbits and hyperbolic flyby orbits at different distances were analyzed using numerical methods. A method to calculate the coverage rate of the orbits was proposed considering the sunlight condition and topographical shading. Then mapping orbits were analyzed in the perspective of coverage rate, mapping time, fuel cost and robustness. Taking nearly spherical asteroid Bennu 101955 and elongated asteroid Eros 433 as examples, the performance of the fly-around orbits and flyby orbits were evaluated, which will provide reference for the mapping phase in future asteroid explorations.