Large Ripples （LRs） on Mars come into the subject of researchers with the acquisition of high resolution image data. LRs are a kind of aeolian bedforms with meter-scale wavelength， and outstanding features of their morphology， bedform patterns， mobility and formation processes. However， due to the limited exploration data， especially the lack of high resolution image data， the research scope and depth are extremely limited， which leads to the long-term neglect of their uniqueness， therefore， researches simply consider them as common sand ripples on Earth. Following the geomorphology law and based on the existing limited research， this paper introduces the morphology， sedimentology and formation mechanism of LRs， and discusses their potential research significance. Compared with ordinary sand ripples， LRs are larger with sinuous and sharp crest lines， asymmetric topographic profiles， the downwind slope angle is much bigger than that of upwind， and slip faces are marked by the presence of grainflows and grainfalls. LRs have strong mobility with obvious longitudinal extension of ridges， and the lateral migration is very small. They have various orientations and network patterns which can be used to inverse the complex wind regimes over a long period of time. Three hierarchical order aeolian bedforms of sand ripples， large ripples， and sand dunes can co-exist. Preliminary explorations show that the sedimentology of LRs is the well sorted fine-to-medium sand. Three formation hypotheses were proposed for LRs： dune hypothesis， impacting hypothesis and fluid-drag hypothesis， with more evidences supporting the fluid-drag hypothesis. LRs are different from normal sand ripples， and their uniqueness is of great significance to comprehend Martian aeolian geomorphology， environmental characteristics， and revolution history， and therefore， they are worth making an intensive study of.