Aerodynamic performance test of single rotors and coaxial rotors is conducted under the low Reynolds number condition. Conceptual model of a Mars helicopter is designed for an exploration of pit craters. Based on the design, single rotor models with a different airfoil, number of blades, and the aspect ratio are chosen for the aerodynamic performance test. And, the coaxial rotor performance test is also conducted with changing a distance between upper and lower rotors. In conclusion, AR = 6 and 4-blades rotor configuration shows the best performance in the test of the single rotor with flat plate configuration. The better distance between upper and lower rotors is 30% of diameter in coaxial rotor test.