Abstract: The edge of Solar system is the outermost fence of the heliosphere that protects the homeland of mankind. In recent years, Voyager 1 and Voyager 2 have reached the edge, leaving some major scientific mysteries in a unresolved state because of the limits of the payload function. Therefore, a specific mission for the edge of Solar system contains huge scientific value. Here we introduce the definition of the edge of Solar system and the main detection elements, summarizes the current status of the missions for the outer heliosphere, including the scientific targets and the scientific payload for the missions. Some major scientific issues in heliophysics, interstellar space physics and Solar system evolution, have been presented, as well as the prospects for the scientific goals for our future interstellar mission.