Abstract: Einstein discovered the special relativity and general relativity at 1905 and 1915 respectively. The most fundamental prediction of the general relativity is the existence of black hole. Now, we believe that there is a supermassive black hole and possibly billion of stellar-mass black holes in each galaxy. It is still unclear whether the intermediate mass of black hole exist or not. There are many indirect evidences for the existence of black holes at different scales by measuring the effects of an object surrounding the black
holes. The international collaboration group for the event horizon telescope try to achieve the high resolution that can resolve the
horizon of the two nearby supermassive black holes (in Milky Way and M87 at the center of Virgo cluster) by adopting a technique
known as very-long-baseline interferometry. For about 10 days in April of 2017, the scientists observed the Sgr A* and M87 by networking eight telescopes around the globe. In April 10 of 2019, the group of the event horizon telescope announced the first photo of the black hole at the center of M87, which is the most direct evidence for the existence of the black hole. This results further support the theory of the general relativity. In last part, I also simply review the possible future Chinese projects that will focus on the black hole physics.