The interaction between lunar plasma and spacecraft may cause surface charging/discharging effects, and degrade the performance of spacecraft. The charging potential is a key factor for discharging process. In order to evaluate charging/discharging effects, it is necessary to obtain the Lunar plasma environment. SWIDA/B on Chang’E-1 are the two scientific instruments of solar wind ion detector which could explore the plasma environment in the 200 km Lunar orbit, thereby deducing the solar wind bulk speed, density and temperature. In this paper we select the data in June 2008 derived from SWIDA sensor. First, we figure out the solar wind ion differential flux and energy spectrum, and then calculate the solar wind parameters such as velocity (300.00–600.00 km/s), plasma density (1–10 cm-3) and plasma temperature (1–20 eV). Finally, we adopt an equivalent circuit model to compute the Lunar spacecraft surface charging voltage which is -7–-70 V.