Located at the edge of the Pacific Ring of Fire, Taiwan is a typical island created by tectonic plate collision where continent building is still active with numerous earthquake activities. With Eurasia supercontinent at her west and the Pacific Ocean at east, Taiwan is in one of the most prevalent monsoon areas. Monsoons and typhoons bring along heavy precipitation that produce great threat of mud slide and land slide in the mountains. In recent years, remote sensing satellites have been developed into a powerful environment monitoring tool. Remote mountain areas can only rely on microwave satellite monitoring during and after heavy rain. Single satellite SAR mission, with its advantages of all-weather capability, repeat pass, high spatial resolution and wide swath, can provide not only in-time coverage at disaster locations, but also environment monitoring, disaster assessment and resource survey. A feasible SAR mission defined with its system analyzed for its important targets imaging has been documented and the key system and subsystems parameters derived need to be verified for the mission requirements establishment and payload development.