Abstract: In this paper, the possible elements of space environment during Martian sample-return missions were identified and their effects on the spacecraft were analyzed. The space environment during Martian sample-return missions involves earth space and interplanetary charged particle environment, Martian atmosphere, Martian landing site surface environment and Martian surface low-pressure discharge and dust charging environment. For earth space and interplanetary charged particle environment, trapped particles in earth radiation belt, solar particle event, galactic cosmic ray and solar wind, and the effect produced by them on total ionizing dose, displacement damage dose, single event effect and surface charging effect were quantitatively analyzed. Martian atmospheric parameters were calculated using the Martian global atmosphere model, and the seasonal variations of optical depth and dust storm were analyzed based on observational data. The ground environment of potential Martian landing sites was analyzed, taking the Tianwen-1 candidate landing site as an example, with focus on the MOLA height, slope gradients, and rock distribution characteristics. In addition, special emphasis was placed on analyzing the effects of low-pressure discharge and dust-charging on the Martian surface. The results form the quantitative conditions for engineering, and can be used to support the mission design for Martian sample-return missions.