China has paid considerable attention to space exploration and made great strides in the field. The first Chinese Mars Exploration Mission will be carried out in 2020. Digital simulation has been proved to be an effective and efficient means for planning and deduction in many fields. Thus, it was introduced for the Mars exploration in this paper and key technologies was researched above three aspects. First of all, complicated time-space benchmark was combed to support the interplanetary simulation. Secondly, the multi-resolution pyramid model and indexing strategy were adopted to preprocess the geographical environment data, which ensured the efficiency of data loading, browsing, and querying. Then, the activity objects were abstracted and modelled based on four aspects, including property, ephemeris, geometry, and behavior. Therefore, a digital simulation system, called Sino-Mars, was developed. The architecture of Sino- Mars consists of five layers, including data collection, data processing, scenario modelling, visualization and application layer. Using the Chinese Mars Exploration Mission slated for 2020 as an example, we demonstrated the capabilities of Sino-Mars for data integration, visualization, process deduction, and auxiliary analysis.