The discovery of living microorganisms deep in the marine sediments and even in the oceanic crust (the marine “deep biosphere”), is one of the most significant and exciting discoveries since the ocean drilling program began almost a half-century ago. Investigation of the deep biosphere has become the most thrilling research frontier for both geological and biological sciences. The “biosphere frontiers” has been listed as one of the four themes in the 10-year plan of the International Ocean Discovery Program (IODP 2012-2023), including deep life, biodiversity and environmental forcing of ecosystems. Here, we introduced the deep biosphere and its environmental features, several completed Integrated Ocean Drilling Program Expeditions, which targeted the subseafloor deep biosphere within the crust and sediments, and highlighted the main progress we have made in deep biosphere and deep life research, especially the contribution of Chinese scientists. Finally, we will give a perspective on the future of deep biosphere research according to the challenge we are facing and the key questions need to be answered.