Abstract: In field dynamic monitoring and investigation of soil and water loss, traditional pen-paper way or portable computer has the drawbacks of inconvenient operation and low efficiency in terms of data collection, information recording and storage. Aiming at the practical demand and experience of field sampling and cross-check of results interpretation, a mobile field investigation system based on iOS platform for dynamic monitoring of soil and water loss was designed. The system is composed of several modules with functions like map, element collection, field sampling, field recheck of indoor interpretation result, data organization and management. This paper introduces the system design scheme to provide convenient and efficient tools for data collection and field recheck of indoor interpretation result.