This paper describes behavior of the shock absorption of Mars lander using aluminum foams. According to Mars atmospheric chemical model, oxygen concentration is constant regardless of altitude; however, observation by Herschel Space Observatory suggested the oxygen is abundant near Mars surface. For continuous observation on Mars, landing is planned using simple and small lander. Therefore, we have proposed expandable landing system using aluminum foams with energy absorption capability. In order to protect the payload, it is important to study landing behavior of the proposed system. In this study, mathematical model is formulated for the landing system and the landing behavior is numerically analyzed. Furthermore, a method to optimize the parameters of the proposed landing system using aluminum foams and numerical analyses shows the validity of the proposed optimization method. In addition to above numerical analyses, experimental validation evaluates the landing performance of the proposed landing system and proposed optimization method is validated.